text: (function (f) {
    if (typeof exports === 'object' && typeof module !== 'undefined') {
      module.exports = f();
    } else if (typeof define === 'function' && define.amd) {
      define([], f);
    } else {
      var g;
      if (typeof window !== 'undefined') {
        g = window;
      } else if (typeof global !== 'undefined') {
        g = global;
      } else if (typeof self !== 'undefined') {
        g = self;
      } else {
        g = this;
      }
      g.chai = f();
    }
  })(function () {
    var define, module, exports;
    return (function () {
      function r(e, n, t) {
        function o(i, f) {
          if (!n[i]) {
            if (!e[i]) {
              var c = 'function' == typeof require && require;
              if (!f && c) return c(i, !0);
              if (u) return u(i, !0);
              var a = new Error("Cannot find module '" + i + "'");
              throw ((a.code = 'MODULE_NOT_FOUND'), a);
            }
            var p = (n[i] = { exports: {} });
            e[i][0].call(
              p.exports,
              function (r) {
                var n = e[i][1][r];
                return o(n || r);
              },
              p,
              p.exports,
              r,
              e,
              n,
              t
            );
          }
          return n[i].exports;
        }
        for (var u = 'function' == typeof require && require, i = 0; i < t.length; i++) o(t[i]);
        return o;
      }
      return r;
    })()(
      {
        1: [
          function (require, module, exports) {
            module.exports = require('./lib/chai');
          },
          { './lib/chai': 2 },
        ],
        2: [
          function (require, module, exports) {
            /*!
             * chai
             * Copyright(c) 2011-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            var used = [];
  
            /*!
             * Chai version
             */
  
            exports.version = '4.2.0';
  
            /*!
             * Assertion Error
             */
  
            exports.AssertionError = require('assertion-error');
  
            /*!
             * Utils for plugins (not exported)
             */
  
            var util = require('./chai/utils');
  
            /**
             * # .use(function)
             *
             * Provides a way to extend the internals of Chai.
             *
             * @param {Function}
             * @returns {this} for chaining
             * @api public
             */
  
            exports.use = function (fn) {
              if (!~used.indexOf(fn)) {
                fn(exports, util);
                used.push(fn);
              }
  
              return exports;
            };
  
            /*!
             * Utility Functions
             */
  
            exports.util = util;
  
            /*!
             * Configuration
             */
  
            var config = require('./chai/config');
            exports.config = config;
  
            /*!
             * Primary `Assertion` prototype
             */
  
            var assertion = require('./chai/assertion');
            exports.use(assertion);
  
            /*!
             * Core Assertions
             */
  
            var core = require('./chai/core/assertions');
            exports.use(core);
  
            /*!
             * Expect interface
             */
  
            var expect = require('./chai/interface/expect');
            exports.use(expect);
  
            /*!
             * Should interface
             */
  
            var should = require('./chai/interface/should');
            exports.use(should);
  
            /*!
             * Assert interface
             */
  
            var assert = require('./chai/interface/assert');
            exports.use(assert);
          },
          {
            './chai/assertion': 3,
            './chai/config': 4,
            './chai/core/assertions': 5,
            './chai/interface/assert': 6,
            './chai/interface/expect': 7,
            './chai/interface/should': 8,
            './chai/utils': 22,
            'assertion-error': 33,
          },
        ],
        3: [
          function (require, module, exports) {
            /*!
             * chai
             * http://chaijs.com
             * Copyright(c) 2011-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            var config = require('./config');
  
            module.exports = function (_chai, util) {
              /*!
               * Module dependencies.
               */
  
              var AssertionError = _chai.AssertionError,
                flag = util.flag;
  
              /*!
               * Module export.
               */
  
              _chai.Assertion = Assertion;
  
              /*!
               * Assertion Constructor
               *
               * Creates object for chaining.
               *
               * `Assertion` objects contain metadata in the form of flags. Three flags can
               * be assigned during instantiation by passing arguments to this constructor:
               *
               * - `object`: This flag contains the target of the assertion. For example, in
               *   the assertion `expect(numKittens).to.equal(7);`, the `object` flag will
               *   contain `numKittens` so that the `equal` assertion can reference it when
               *   needed.
               *
               * - `message`: This flag contains an optional custom error message to be
               *   prepended to the error message that's generated by the assertion when it
               *   fails.
               *
               * - `ssfi`: This flag stands for "start stack function indicator". It
               *   contains a function reference that serves as the starting point for
               *   removing frames from the stack trace of the error that's created by the
               *   assertion when it fails. The goal is to provide a cleaner stack trace to
               *   end users by removing Chai's internal functions. Note that it only works
               *   in environments that support `Error.captureStackTrace`, and only when
               *   `Chai.config.includeStack` hasn't been set to `false`.
               *
               * - `lockSsfi`: This flag controls whether or not the given `ssfi` flag
               *   should retain its current value, even as assertions are chained off of
               *   this object. This is usually set to `true` when creating a new assertion
               *   from within another assertion. It's also temporarily set to `true` before
               *   an overwritten assertion gets called by the overwriting assertion.
               *
               * @param {Mixed} obj target of the assertion
               * @param {String} msg (optional) custom error message
               * @param {Function} ssfi (optional) starting point for removing stack frames
               * @param {Boolean} lockSsfi (optional) whether or not the ssfi flag is locked
               * @api private
               */
  
              function Assertion(obj, msg, ssfi, lockSsfi) {
                flag(this, 'ssfi', ssfi || Assertion);
                flag(this, 'lockSsfi', lockSsfi);
                flag(this, 'object', obj);
                flag(this, 'message', msg);
  
                return util.proxify(this);
              }
  
              Object.defineProperty(Assertion, 'includeStack', {
                get: function () {
                  console.warn(
                    'Assertion.includeStack is deprecated, use chai.config.includeStack instead.'
                  );
                  return config.includeStack;
                },
                set: function (value) {
                  console.warn(
                    'Assertion.includeStack is deprecated, use chai.config.includeStack instead.'
                  );
                  config.includeStack = value;
                },
              });
  
              Object.defineProperty(Assertion, 'showDiff', {
                get: function () {
                  console.warn('Assertion.showDiff is deprecated, use chai.config.showDiff instead.');
                  return config.showDiff;
                },
                set: function (value) {
                  console.warn('Assertion.showDiff is deprecated, use chai.config.showDiff instead.');
                  config.showDiff = value;
                },
              });
  
              Assertion.addProperty = function (name, fn) {
                util.addProperty(this.prototype, name, fn);
              };
  
              Assertion.addMethod = function (name, fn) {
                util.addMethod(this.prototype, name, fn);
              };
  
              Assertion.addChainableMethod = function (name, fn, chainingBehavior) {
                util.addChainableMethod(this.prototype, name, fn, chainingBehavior);
              };
  
              Assertion.overwriteProperty = function (name, fn) {
                util.overwriteProperty(this.prototype, name, fn);
              };
  
              Assertion.overwriteMethod = function (name, fn) {
                util.overwriteMethod(this.prototype, name, fn);
              };
  
              Assertion.overwriteChainableMethod = function (name, fn, chainingBehavior) {
                util.overwriteChainableMethod(this.prototype, name, fn, chainingBehavior);
              };
  
              /**
               * ### .assert(expression, message, negateMessage, expected, actual, showDiff)
               *
               * Executes an expression and check expectations. Throws AssertionError for reporting if test doesn't pass.
               *
               * @name assert
               * @param {Philosophical} expression to be tested
               * @param {String|Function} message or function that returns message to display if expression fails
               * @param {String|Function} negatedMessage or function that returns negatedMessage to display if negated expression fails
               * @param {Mixed} expected value (remember to check for negation)
               * @param {Mixed} actual (optional) will default to `this.obj`
               * @param {Boolean} showDiff (optional) when set to `true`, assert will display a diff in addition to the message if expression fails
               * @api private
               */
  
              Assertion.prototype.assert = function (
                expr,
                msg,
                negateMsg,
                expected,
                _actual,
                showDiff
              ) {
                var ok = util.test(this, arguments);
                if (false !== showDiff) showDiff = true;
                if (undefined === expected && undefined === _actual) showDiff = false;
                if (true !== config.showDiff) showDiff = false;
  
                if (!ok) {
                  msg = util.getMessage(this, arguments);
                  var actual = util.getActual(this, arguments);
                  throw new AssertionError(
                    msg,
                    {
                      actual: actual,
                      expected: expected,
                      showDiff: showDiff,
                    },
                    config.includeStack ? this.assert : flag(this, 'ssfi')
                  );
                }
              };
  
              /*!
               * ### ._obj
               *
               * Quick reference to stored `actual` value for plugin developers.
               *
               * @api private
               */
  
              Object.defineProperty(Assertion.prototype, '_obj', {
                get: function () {
                  return flag(this, 'object');
                },
                set: function (val) {
                  flag(this, 'object', val);
                },
              });
            };
          },
          { './config': 4 },
        ],
        4: [
          function (require, module, exports) {
            module.exports = {
              /**
               * ### config.includeStack
               *
               * User configurable property, influences whether stack trace
               * is included in Assertion error message. Default of false
               * suppresses stack trace in the error message.
               *
               *     chai.config.includeStack = true;  // enable stack on error
               *
               * @param {Boolean}
               * @api public
               */
  
              includeStack: false,
  
              /**
               * ### config.showDiff
               *
               * User configurable property, influences whether or not
               * the `showDiff` flag should be included in the thrown
               * AssertionErrors. `false` will always be `false`; `true`
               * will be true when the assertion has requested a diff
               * be shown.
               *
               * @param {Boolean}
               * @api public
               */
  
              showDiff: true,
  
              /**
               * ### config.truncateThreshold
               *
               * User configurable property, sets length threshold for actual and
               * expected values in assertion errors. If this threshold is exceeded, for
               * example for large data structures, the value is replaced with something
               * like `[ Array(3) ]` or `{ Object (prop1, prop2) }`.
               *
               * Set it to zero if you want to disable truncating altogether.
               *
               * This is especially userful when doing assertions on arrays: having this
               * set to a reasonable large value makes the failure messages readily
               * inspectable.
               *
               *     chai.config.truncateThreshold = 0;  // disable truncating
               *
               * @param {Number}
               * @api public
               */
  
              truncateThreshold: 40,
  
              /**
               * ### config.useProxy
               *
               * User configurable property, defines if chai will use a Proxy to throw
               * an error when a non-existent property is read, which protects users
               * from typos when using property-based assertions.
               *
               * Set it to false if you want to disable this feature.
               *
               *     chai.config.useProxy = false;  // disable use of Proxy
               *
               * This feature is automatically disabled regardless of this config value
               * in environments that don't support proxies.
               *
               * @param {Boolean}
               * @api public
               */
  
              useProxy: true,
  
              /**
               * ### config.proxyExcludedKeys
               *
               * User configurable property, defines which properties should be ignored
               * instead of throwing an error if they do not exist on the assertion.
               * This is only applied if the environment Chai is running in supports proxies and
               * if the `useProxy` configuration setting is enabled.
               * By default, `then` and `inspect` will not throw an error if they do not exist on the
               * assertion object because the `.inspect` property is read by `util.inspect` (for example, when
               * using `console.log` on the assertion object) and `.then` is necessary for promise type-checking.
               *
               *     // By default these keys will not throw an error if they do not exist on the assertion object
               *     chai.config.proxyExcludedKeys = ['then', 'inspect'];
               *
               * @param {Array}
               * @api public
               */
  
              proxyExcludedKeys: ['then', 'catch', 'inspect', 'toJSON'],
            };
          },
          {},
        ],
        5: [
          function (require, module, exports) {
            /*!
             * chai
             * http://chaijs.com
             * Copyright(c) 2011-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            module.exports = function (chai, _) {
              var Assertion = chai.Assertion,
                AssertionError = chai.AssertionError,
                flag = _.flag;
  
              /**
               * ### Language Chains
               *
               * The following are provided as chainable getters to improve the readability
               * of your assertions.
               *
               * **Chains**
               *
               * - to
               * - be
               * - been
               * - is
               * - that
               * - which
               * - and
               * - has
               * - have
               * - with
               * - at
               * - of
               * - same
               * - but
               * - does
               * - still
               *
               * @name language chains
               * @namespace BDD
               * @api public
               */
  
              [
                'to',
                'be',
                'been',
                'is',
                'and',
                'has',
                'have',
                'with',
                'that',
                'which',
                'at',
                'of',
                'same',
                'but',
                'does',
                'still',
              ].forEach(function (chain) {
                Assertion.addProperty(chain);
              });
  
              /**
               * ### .not
               *
               * Negates all assertions that follow in the chain.
               *
               *     expect(function () {}).to.not.throw();
               *     expect({a: 1}).to.not.have.property('b');
               *     expect([1, 2]).to.be.an('array').that.does.not.include(3);
               *
               * Just because you can negate any assertion with `.not` doesn't mean you
               * should. With great power comes great responsibility. It's often best to
               * assert that the one expected output was produced, rather than asserting
               * that one of countless unexpected outputs wasn't produced. See individual
               * assertions for specific guidance.
               *
               *     expect(2).to.equal(2); // Recommended
               *     expect(2).to.not.equal(1); // Not recommended
               *
               * @name not
               * @namespace BDD
               * @api public
               */
  
              Assertion.addProperty('not', function () {
                flag(this, 'negate', true);
              });
  
              /**
               * ### .deep
               *
               * Causes all `.equal`, `.include`, `.members`, `.keys`, and `.property`
               * assertions that follow in the chain to use deep equality instead of strict
               * (`===`) equality. See the `deep-eql` project page for info on the deep
               * equality algorithm: https://github.com/chaijs/deep-eql.
               *
               *     // Target object deeply (but not strictly) equals `{a: 1}`
               *     expect({a: 1}).to.deep.equal({a: 1});
               *     expect({a: 1}).to.not.equal({a: 1});
               *
               *     // Target array deeply (but not strictly) includes `{a: 1}`
               *     expect([{a: 1}]).to.deep.include({a: 1});
               *     expect([{a: 1}]).to.not.include({a: 1});
               *
               *     // Target object deeply (but not strictly) includes `x: {a: 1}`
               *     expect({x: {a: 1}}).to.deep.include({x: {a: 1}});
               *     expect({x: {a: 1}}).to.not.include({x: {a: 1}});
               *
               *     // Target array deeply (but not strictly) has member `{a: 1}`
               *     expect([{a: 1}]).to.have.deep.members([{a: 1}]);
               *     expect([{a: 1}]).to.not.have.members([{a: 1}]);
               *
               *     // Target set deeply (but not strictly) has key `{a: 1}`
               *     expect(new Set([{a: 1}])).to.have.deep.keys([{a: 1}]);
               *     expect(new Set([{a: 1}])).to.not.have.keys([{a: 1}]);
               *
               *     // Target object deeply (but not strictly) has property `x: {a: 1}`
               *     expect({x: {a: 1}}).to.have.deep.property('x', {a: 1});
               *     expect({x: {a: 1}}).to.not.have.property('x', {a: 1});
               *
               * @name deep
               * @namespace BDD
               * @api public
               */
  
              Assertion.addProperty('deep', function () {
                flag(this, 'deep', true);
              });
  
              /**
               * ### .nested
               *
               * Enables dot- and bracket-notation in all `.property` and `.include`
               * assertions that follow in the chain.
               *
               *     expect({a: {b: ['x', 'y']}}).to.have.nested.property('a.b[1]');
               *     expect({a: {b: ['x', 'y']}}).to.nested.include({'a.b[1]': 'y'});
               *
               * If `.` or `[]` are part of an actual property name, they can be escaped by
               * adding two backslashes before them.
               *
               *     expect({'.a': {'[b]': 'x'}}).to.have.nested.property('\\.a.\\[b\\]');
               *     expect({'.a': {'[b]': 'x'}}).to.nested.include({'\\.a.\\[b\\]': 'x'});
               *
               * `.nested` cannot be combined with `.own`.
               *
               * @name nested
               * @namespace BDD
               * @api public
               */
  
              Assertion.addProperty('nested', function () {
                flag(this, 'nested', true);
              });
  
              /**
               * ### .own
               *
               * Causes all `.property` and `.include` assertions that follow in the chain
               * to ignore inherited properties.
               *
               *     Object.prototype.b = 2;
               *
               *     expect({a: 1}).to.have.own.property('a');
               *     expect({a: 1}).to.have.property('b');
               *     expect({a: 1}).to.not.have.own.property('b');
               *
               *     expect({a: 1}).to.own.include({a: 1});
               *     expect({a: 1}).to.include({b: 2}).but.not.own.include({b: 2});
               *
               * `.own` cannot be combined with `.nested`.
               *
               * @name own
               * @namespace BDD
               * @api public
               */
  
              Assertion.addProperty('own', function () {
                flag(this, 'own', true);
              });
  
              /**
               * ### .ordered
               *
               * Causes all `.members` assertions that follow in the chain to require that
               * members be in the same order.
               *
               *     expect([1, 2]).to.have.ordered.members([1, 2])
               *       .but.not.have.ordered.members([2, 1]);
               *
               * When `.include` and `.ordered` are combined, the ordering begins at the
               * start of both arrays.
               *
               *     expect([1, 2, 3]).to.include.ordered.members([1, 2])
               *       .but.not.include.ordered.members([2, 3]);
               *
               * @name ordered
               * @namespace BDD
               * @api public
               */
  
              Assertion.addProperty('ordered', function () {
                flag(this, 'ordered', true);
              });
  
              /**
               * ### .any
               *
               * Causes all `.keys` assertions that follow in the chain to only require that
               * the target have at least one of the given keys. This is the opposite of
               * `.all`, which requires that the target have all of the given keys.
               *
               *     expect({a: 1, b: 2}).to.not.have.any.keys('c', 'd');
               *
               * See the `.keys` doc for guidance on when to use `.any` or `.all`.
               *
               * @name any
               * @namespace BDD
               * @api public
               */
  
              Assertion.addProperty('any', function () {
                flag(this, 'any', true);
                flag(this, 'all', false);
              });
  
              /**
               * ### .all
               *
               * Causes all `.keys` assertions that follow in the chain to require that the
               * target have all of the given keys. This is the opposite of `.any`, which
               * only requires that the target have at least one of the given keys.
               *
               *     expect({a: 1, b: 2}).to.have.all.keys('a', 'b');
               *
               * Note that `.all` is used by default when neither `.all` nor `.any` are
               * added earlier in the chain. However, it's often best to add `.all` anyway
               * because it improves readability.
               *
               * See the `.keys` doc for guidance on when to use `.any` or `.all`.
               *
               * @name all
               * @namespace BDD
               * @api public
               */
  
              Assertion.addProperty('all', function () {
                flag(this, 'all', true);
                flag(this, 'any', false);
              });
  
              /**
               * ### .a(type[, msg])
               *
               * Asserts that the target's type is equal to the given string `type`. Types
               * are case insensitive. See the `type-detect` project page for info on the
               * type detection algorithm: https://github.com/chaijs/type-detect.
               *
               *     expect('foo').to.be.a('string');
               *     expect({a: 1}).to.be.an('object');
               *     expect(null).to.be.a('null');
               *     expect(undefined).to.be.an('undefined');
               *     expect(new Error).to.be.an('error');
               *     expect(Promise.resolve()).to.be.a('promise');
               *     expect(new Float32Array).to.be.a('float32array');
               *     expect(Symbol()).to.be.a('symbol');
               *
               * `.a` supports objects that have a custom type set via `Symbol.toStringTag`.
               *
               *     var myObj = {
               *       [Symbol.toStringTag]: 'myCustomType'
               *     };
               *
               *     expect(myObj).to.be.a('myCustomType').but.not.an('object');
               *
               * It's often best to use `.a` to check a target's type before making more
               * assertions on the same target. That way, you avoid unexpected behavior from
               * any assertion that does different things based on the target's type.
               *
               *     expect([1, 2, 3]).to.be.an('array').that.includes(2);
               *     expect([]).to.be.an('array').that.is.empty;
               *
               * Add `.not` earlier in the chain to negate `.a`. However, it's often best to
               * assert that the target is the expected type, rather than asserting that it
               * isn't one of many unexpected types.
               *
               *     expect('foo').to.be.a('string'); // Recommended
               *     expect('foo').to.not.be.an('array'); // Not recommended
               *
               * `.a` accepts an optional `msg` argument which is a custom error message to
               * show when the assertion fails. The message can also be given as the second
               * argument to `expect`.
               *
               *     expect(1).to.be.a('string', 'nooo why fail??');
               *     expect(1, 'nooo why fail??').to.be.a('string');
               *
               * `.a` can also be used as a language chain to improve the readability of
               * your assertions.
               *
               *     expect({b: 2}).to.have.a.property('b');
               *
               * The alias `.an` can be used interchangeably with `.a`.
               *
               * @name a
               * @alias an
               * @param {String} type
               * @param {String} msg _optional_
               * @namespace BDD
               * @api public
               */
  
              function an(type, msg) {
                if (msg) flag(this, 'message', msg);
                type = type.toLowerCase();
                var obj = flag(this, 'object'),
                  article = ~['a', 'e', 'i', 'o', 'u'].indexOf(type.charAt(0)) ? 'an ' : 'a ';
  
                this.assert(
                  type === _.type(obj).toLowerCase(),
                  'expected #{this} to be ' + article + type,
                  'expected #{this} not to be ' + article + type
                );
              }
  
              Assertion.addChainableMethod('an', an);
              Assertion.addChainableMethod('a', an);
  
              /**
               * ### .include(val[, msg])
               *
               * When the target is a string, `.include` asserts that the given string `val`
               * is a substring of the target.
               *
               *     expect('foobar').to.include('foo');
               *
               * When the target is an array, `.include` asserts that the given `val` is a
               * member of the target.
               *
               *     expect([1, 2, 3]).to.include(2);
               *
               * When the target is an object, `.include` asserts that the given object
               * `val`'s properties are a subset of the target's properties.
               *
               *     expect({a: 1, b: 2, c: 3}).to.include({a: 1, b: 2});
               *
               * When the target is a Set or WeakSet, `.include` asserts that the given `val` is a
               * member of the target. SameValueZero equality algorithm is used.
               *
               *     expect(new Set([1, 2])).to.include(2);
               *
               * When the target is a Map, `.include` asserts that the given `val` is one of
               * the values of the target. SameValueZero equality algorithm is used.
               *
               *     expect(new Map([['a', 1], ['b', 2]])).to.include(2);
               *
               * Because `.include` does different things based on the target's type, it's
               * important to check the target's type before using `.include`. See the `.a`
               * doc for info on testing a target's type.
               *
               *     expect([1, 2, 3]).to.be.an('array').that.includes(2);
               *
               * By default, strict (`===`) equality is used to compare array members and
               * object properties. Add `.deep` earlier in the chain to use deep equality
               * instead (WeakSet targets are not supported). See the `deep-eql` project
               * page for info on the deep equality algorithm: https://github.com/chaijs/deep-eql.
               *
               *     // Target array deeply (but not strictly) includes `{a: 1}`
               *     expect([{a: 1}]).to.deep.include({a: 1});
               *     expect([{a: 1}]).to.not.include({a: 1});
               *
               *     // Target object deeply (but not strictly) includes `x: {a: 1}`
               *     expect({x: {a: 1}}).to.deep.include({x: {a: 1}});
               *     expect({x: {a: 1}}).to.not.include({x: {a: 1}});
               *
               * By default, all of the target's properties are searched when working with
               * objects. This includes properties that are inherited and/or non-enumerable.
               * Add `.own` earlier in the chain to exclude the target's inherited
               * properties from the search.
               *
               *     Object.prototype.b = 2;
               *
               *     expect({a: 1}).to.own.include({a: 1});
               *     expect({a: 1}).to.include({b: 2}).but.not.own.include({b: 2});
               *
               * Note that a target object is always only searched for `val`'s own
               * enumerable properties.
               *
               * `.deep` and `.own` can be combined.
               *
               *     expect({a: {b: 2}}).to.deep.own.include({a: {b: 2}});
               *
               * Add `.nested` earlier in the chain to enable dot- and bracket-notation when
               * referencing nested properties.
               *
               *     expect({a: {b: ['x', 'y']}}).to.nested.include({'a.b[1]': 'y'});
               *
               * If `.` or `[]` are part of an actual property name, they can be escaped by
               * adding two backslashes before them.
               *
               *     expect({'.a': {'[b]': 2}}).to.nested.include({'\\.a.\\[b\\]': 2});
               *
               * `.deep` and `.nested` can be combined.
               *
               *     expect({a: {b: [{c: 3}]}}).to.deep.nested.include({'a.b[0]': {c: 3}});
               *
               * `.own` and `.nested` cannot be combined.
               *
               * Add `.not` earlier in the chain to negate `.include`.
               *
               *     expect('foobar').to.not.include('taco');
               *     expect([1, 2, 3]).to.not.include(4);
               *
               * However, it's dangerous to negate `.include` when the target is an object.
               * The problem is that it creates uncertain expectations by asserting that the
               * target object doesn't have all of `val`'s key/value pairs but may or may
               * not have some of them. It's often best to identify the exact output that's
               * expected, and then write an assertion that only accepts that exact output.
               *
               * When the target object isn't even expected to have `val`'s keys, it's
               * often best to assert exactly that.
               *
               *     expect({c: 3}).to.not.have.any.keys('a', 'b'); // Recommended
               *     expect({c: 3}).to.not.include({a: 1, b: 2}); // Not recommended
               *
               * When the target object is expected to have `val`'s keys, it's often best to
               * assert that each of the properties has its expected value, rather than
               * asserting that each property doesn't have one of many unexpected values.
               *
               *     expect({a: 3, b: 4}).to.include({a: 3, b: 4}); // Recommended
               *     expect({a: 3, b: 4}).to.not.include({a: 1, b: 2}); // Not recommended
               *
               * `.include` accepts an optional `msg` argument which is a custom error
               * message to show when the assertion fails. The message can also be given as
               * the second argument to `expect`.
               *
               *     expect([1, 2, 3]).to.include(4, 'nooo why fail??');
               *     expect([1, 2, 3], 'nooo why fail??').to.include(4);
               *
               * `.include` can also be used as a language chain, causing all `.members` and
               * `.keys` assertions that follow in the chain to require the target to be a
               * superset of the expected set, rather than an identical set. Note that
               * `.members` ignores duplicates in the subset when `.include` is added.
               *
               *     // Target object's keys are a superset of ['a', 'b'] but not identical
               *     expect({a: 1, b: 2, c: 3}).to.include.all.keys('a', 'b');
               *     expect({a: 1, b: 2, c: 3}).to.not.have.all.keys('a', 'b');
               *
               *     // Target array is a superset of [1, 2] but not identical
               *     expect([1, 2, 3]).to.include.members([1, 2]);
               *     expect([1, 2, 3]).to.not.have.members([1, 2]);
               *
               *     // Duplicates in the subset are ignored
               *     expect([1, 2, 3]).to.include.members([1, 2, 2, 2]);
               *
               * Note that adding `.any` earlier in the chain causes the `.keys` assertion
               * to ignore `.include`.
               *
               *     // Both assertions are identical
               *     expect({a: 1}).to.include.any.keys('a', 'b');
               *     expect({a: 1}).to.have.any.keys('a', 'b');
               *
               * The aliases `.includes`, `.contain`, and `.contains` can be used
               * interchangeably with `.include`.
               *
               * @name include
               * @alias contain
               * @alias includes
               * @alias contains
               * @param {Mixed} val
               * @param {String} msg _optional_
               * @namespace BDD
               * @api public
               */
  
              function SameValueZero(a, b) {
                return (_.isNaN(a) && _.isNaN(b)) || a === b;
              }
  
              function includeChainingBehavior() {
                flag(this, 'contains', true);
              }
  
              function include(val, msg) {
                if (msg) flag(this, 'message', msg);
  
                var obj = flag(this, 'object'),
                  objType = _.type(obj).toLowerCase(),
                  flagMsg = flag(this, 'message'),
                  negate = flag(this, 'negate'),
                  ssfi = flag(this, 'ssfi'),
                  isDeep = flag(this, 'deep'),
                  descriptor = isDeep ? 'deep ' : '';
  
                flagMsg = flagMsg ? flagMsg + ': ' : '';
  
                var included = false;
  
                switch (objType) {
                  case 'string':
                    included = obj.indexOf(val) !== -1;
                    break;
  
                  case 'weakset':
                    if (isDeep) {
                      throw new AssertionError(
                        flagMsg + 'unable to use .deep.include with WeakSet',
                        undefined,
                        ssfi
                      );
                    }
  
                    included = obj.has(val);
                    break;
  
                  case 'map':
                    var isEql = isDeep ? _.eql : SameValueZero;
                    obj.forEach(function (item) {
                      included = included || isEql(item, val);
                    });
                    break;
  
                  case 'set':
                    if (isDeep) {
                      obj.forEach(function (item) {
                        included = included || _.eql(item, val);
                      });
                    } else {
                      included = obj.has(val);
                    }
                    break;
  
                  case 'array':
                    if (isDeep) {
                      included = obj.some(function (item) {
                        return _.eql(item, val);
                      });
                    } else {
                      included = obj.indexOf(val) !== -1;
                    }
                    break;
  
                  default:
                    // This block is for asserting a subset of properties in an object.
                    // `_.expectTypes` isn't used here because `.include` should work with
                    // objects with a custom `@@toStringTag`.
                    if (val !== Object(val)) {
                      throw new AssertionError(
                        flagMsg +
                          'object tested must be an array, a map, an object,' +
                          ' a set, a string, or a weakset, but ' +
                          objType +
                          ' given',
                        undefined,
                        ssfi
                      );
                    }
  
                    var props = Object.keys(val),
                      firstErr = null,
                      numErrs = 0;
  
                    props.forEach(function (prop) {
                      var propAssertion = new Assertion(obj);
                      _.transferFlags(this, propAssertion, true);
                      flag(propAssertion, 'lockSsfi', true);
  
                      if (!negate || props.length === 1) {
                        propAssertion.property(prop, val[prop]);
                        return;
                      }
  
                      try {
                        propAssertion.property(prop, val[prop]);
                      } catch (err) {
                        if (!_.checkError.compatibleConstructor(err, AssertionError)) {
                          throw err;
                        }
                        if (firstErr === null) firstErr = err;
                        numErrs++;
                      }
                    }, this);
  
                    // When validating .not.include with multiple properties, we only want
                    // to throw an assertion error if all of the properties are included,
                    // in which case we throw the first property assertion error that we
                    // encountered.
                    if (negate && props.length > 1 && numErrs === props.length) {
                      throw firstErr;
                    }
                    return;
                }
  
                // Assert inclusion in collection or substring in a string.
                this.assert(
                  included,
                  'expected #{this} to ' + descriptor + 'include ' + _.inspect(val),
                  'expected #{this} to not ' + descriptor + 'include ' + _.inspect(val)
                );
              }
  
              Assertion.addChainableMethod('include', include, includeChainingBehavior);
              Assertion.addChainableMethod('contain', include, includeChainingBehavior);
              Assertion.addChainableMethod('contains', include, includeChainingBehavior);
              Assertion.addChainableMethod('includes', include, includeChainingBehavior);
  
              /**
               * ### .ok
               *
               * Asserts that the target is a truthy value (considered `true` in boolean context).
               * However, it's often best to assert that the target is strictly (`===`) or
               * deeply equal to its expected value.
               *
               *     expect(1).to.equal(1); // Recommended
               *     expect(1).to.be.ok; // Not recommended
               *
               *     expect(true).to.be.true; // Recommended
               *     expect(true).to.be.ok; // Not recommended
               *
               * Add `.not` earlier in the chain to negate `.ok`.
               *
               *     expect(0).to.equal(0); // Recommended
               *     expect(0).to.not.be.ok; // Not recommended
               *
               *     expect(false).to.be.false; // Recommended
               *     expect(false).to.not.be.ok; // Not recommended
               *
               *     expect(null).to.be.null; // Recommended
               *     expect(null).to.not.be.ok; // Not recommended
               *
               *     expect(undefined).to.be.undefined; // Recommended
               *     expect(undefined).to.not.be.ok; // Not recommended
               *
               * A custom error message can be given as the second argument to `expect`.
               *
               *     expect(false, 'nooo why fail??').to.be.ok;
               *
               * @name ok
               * @namespace BDD
               * @api public
               */
  
              Assertion.addProperty('ok', function () {
                this.assert(
                  flag(this, 'object'),
                  'expected #{this} to be truthy',
                  'expected #{this} to be falsy'
                );
              });
  
              /**
               * ### .true
               *
               * Asserts that the target is strictly (`===`) equal to `true`.
               *
               *     expect(true).to.be.true;
               *
               * Add `.not` earlier in the chain to negate `.true`. However, it's often best
               * to assert that the target is equal to its expected value, rather than not
               * equal to `true`.
               *
               *     expect(false).to.be.false; // Recommended
               *     expect(false).to.not.be.true; // Not recommended
               *
               *     expect(1).to.equal(1); // Recommended
               *     expect(1).to.not.be.true; // Not recommended
               *
               * A custom error message can be given as the second argument to `expect`.
               *
               *     expect(false, 'nooo why fail??').to.be.true;
               *
               * @name true
               * @namespace BDD
               * @api public
               */
  
              Assertion.addProperty('true', function () {
                this.assert(
                  true === flag(this, 'object'),
                  'expected #{this} to be true',
                  'expected #{this} to be false',
                  flag(this, 'negate') ? false : true
                );
              });
  
              /**
               * ### .false
               *
               * Asserts that the target is strictly (`===`) equal to `false`.
               *
               *     expect(false).to.be.false;
               *
               * Add `.not` earlier in the chain to negate `.false`. However, it's often
               * best to assert that the target is equal to its expected value, rather than
               * not equal to `false`.
               *
               *     expect(true).to.be.true; // Recommended
               *     expect(true).to.not.be.false; // Not recommended
               *
               *     expect(1).to.equal(1); // Recommended
               *     expect(1).to.not.be.false; // Not recommended
               *
               * A custom error message can be given as the second argument to `expect`.
               *
               *     expect(true, 'nooo why fail??').to.be.false;
               *
               * @name false
               * @namespace BDD
               * @api public
               */
  
              Assertion.addProperty('false', function () {
                this.assert(
                  false === flag(this, 'object'),
                  'expected #{this} to be false',
                  'expected #{this} to be true',
                  flag(this, 'negate') ? true : false
                );
              });
  
              /**
               * ### .null
               *
               * Asserts that the target is strictly (`===`) equal to `null`.
               *
               *     expect(null).to.be.null;
               *
               * Add `.not` earlier in the chain to negate `.null`. However, it's often best
               * to assert that the target is equal to its expected value, rather than not
               * equal to `null`.
               *
               *     expect(1).to.equal(1); // Recommended
               *     expect(1).to.not.be.null; // Not recommended
               *
               * A custom error message can be given as the second argument to `expect`.
               *
               *     expect(42, 'nooo why fail??').to.be.null;
               *
               * @name null
               * @namespace BDD
               * @api public
               */
  
              Assertion.addProperty('null', function () {
                this.assert(
                  null === flag(this, 'object'),
                  'expected #{this} to be null',
                  'expected #{this} not to be null'
                );
              });
  
              /**
               * ### .undefined
               *
               * Asserts that the target is strictly (`===`) equal to `undefined`.
               *
               *     expect(undefined).to.be.undefined;
               *
               * Add `.not` earlier in the chain to negate `.undefined`. However, it's often
               * best to assert that the target is equal to its expected value, rather than
               * not equal to `undefined`.
               *
               *     expect(1).to.equal(1); // Recommended
               *     expect(1).to.not.be.undefined; // Not recommended
               *
               * A custom error message can be given as the second argument to `expect`.
               *
               *     expect(42, 'nooo why fail??').to.be.undefined;
               *
               * @name undefined
               * @namespace BDD
               * @api public
               */
  
              Assertion.addProperty('undefined', function () {
                this.assert(
                  undefined === flag(this, 'object'),
                  'expected #{this} to be undefined',
                  'expected #{this} not to be undefined'
                );
              });
  
              /**
               * ### .NaN
               *
               * Asserts that the target is exactly `NaN`.
               *
               *     expect(NaN).to.be.NaN;
               *
               * Add `.not` earlier in the chain to negate `.NaN`. However, it's often best
               * to assert that the target is equal to its expected value, rather than not
               * equal to `NaN`.
               *
               *     expect('foo').to.equal('foo'); // Recommended
               *     expect('foo').to.not.be.NaN; // Not recommended
               *
               * A custom error message can be given as the second argument to `expect`.
               *
               *     expect(42, 'nooo why fail??').to.be.NaN;
               *
               * @name NaN
               * @namespace BDD
               * @api public
               */
  
              Assertion.addProperty('NaN', function () {
                this.assert(
                  _.isNaN(flag(this, 'object')),
                  'expected #{this} to be NaN',
                  'expected #{this} not to be NaN'
                );
              });
  
              /**
               * ### .exist
               *
               * Asserts that the target is not strictly (`===`) equal to either `null` or
               * `undefined`. However, it's often best to assert that the target is equal to
               * its expected value.
               *
               *     expect(1).to.equal(1); // Recommended
               *     expect(1).to.exist; // Not recommended
               *
               *     expect(0).to.equal(0); // Recommended
               *     expect(0).to.exist; // Not recommended
               *
               * Add `.not` earlier in the chain to negate `.exist`.
               *
               *     expect(null).to.be.null; // Recommended
               *     expect(null).to.not.exist; // Not recommended
               *
               *     expect(undefined).to.be.undefined; // Recommended
               *     expect(undefined).to.not.exist; // Not recommended
               *
               * A custom error message can be given as the second argument to `expect`.
               *
               *     expect(null, 'nooo why fail??').to.exist;
               *
               * @name exist
               * @namespace BDD
               * @api public
               */
  
              Assertion.addProperty('exist', function () {
                var val = flag(this, 'object');
                this.assert(
                  val !== null && val !== undefined,
                  'expected #{this} to exist',
                  'expected #{this} to not exist'
                );
              });
  
              /**
               * ### .empty
               *
               * When the target is a string or array, `.empty` asserts that the target's
               * `length` property is strictly (`===`) equal to `0`.
               *
               *     expect([]).to.be.empty;
               *     expect('').to.be.empty;
               *
               * When the target is a map or set, `.empty` asserts that the target's `size`
               * property is strictly equal to `0`.
               *
               *     expect(new Set()).to.be.empty;
               *     expect(new Map()).to.be.empty;
               *
               * When the target is a non-function object, `.empty` asserts that the target
               * doesn't have any own enumerable properties. Properties with Symbol-based
               * keys are excluded from the count.
               *
               *     expect({}).to.be.empty;
               *
               * Because `.empty` does different things based on the target's type, it's
               * important to check the target's type before using `.empty`. See the `.a`
               * doc for info on testing a target's type.
               *
               *     expect([]).to.be.an('array').that.is.empty;
               *
               * Add `.not` earlier in the chain to negate `.empty`. However, it's often
               * best to assert that the target contains its expected number of values,
               * rather than asserting that it's not empty.
               *
               *     expect([1, 2, 3]).to.have.lengthOf(3); // Recommended
               *     expect([1, 2, 3]).to.not.be.empty; // Not recommended
               *
               *     expect(new Set([1, 2, 3])).to.have.property('size', 3); // Recommended
               *     expect(new Set([1, 2, 3])).to.not.be.empty; // Not recommended
               *
               *     expect(Object.keys({a: 1})).to.have.lengthOf(1); // Recommended
               *     expect({a: 1}).to.not.be.empty; // Not recommended
               *
               * A custom error message can be given as the second argument to `expect`.
               *
               *     expect([1, 2, 3], 'nooo why fail??').to.be.empty;
               *
               * @name empty
               * @namespace BDD
               * @api public
               */
  
              Assertion.addProperty('empty', function () {
                var val = flag(this, 'object'),
                  ssfi = flag(this, 'ssfi'),
                  flagMsg = flag(this, 'message'),
                  itemsCount;
  
                flagMsg = flagMsg ? flagMsg + ': ' : '';
  
                switch (_.type(val).toLowerCase()) {
                  case 'array':
                  case 'string':
                    itemsCount = val.length;
                    break;
                  case 'map':
                  case 'set':
                    itemsCount = val.size;
                    break;
                  case 'weakmap':
                  case 'weakset':
                    throw new AssertionError(
                      flagMsg + '.empty was passed a weak collection',
                      undefined,
                      ssfi
                    );
                  case 'function':
                    var msg = flagMsg + '.empty was passed a function ' + _.getName(val);
                    throw new AssertionError(msg.trim(), undefined, ssfi);
                  default:
                    if (val !== Object(val)) {
                      throw new AssertionError(
                        flagMsg + '.empty was passed non-string primitive ' + _.inspect(val),
                        undefined,
                        ssfi
                      );
                    }
                    itemsCount = Object.keys(val).length;
                }
  
                this.assert(
                  0 === itemsCount,
                  'expected #{this} to be empty',
                  'expected #{this} not to be empty'
                );
              });
  
              /**
               * ### .arguments
               *
               * Asserts that the target is an `arguments` object.
               *
               *     function test () {
               *       expect(arguments).to.be.arguments;
               *     }
               *
               *     test();
               *
               * Add `.not` earlier in the chain to negate `.arguments`. However, it's often
               * best to assert which type the target is expected to be, rather than
               * asserting that its not an `arguments` object.
               *
               *     expect('foo').to.be.a('string'); // Recommended
               *     expect('foo').to.not.be.arguments; // Not recommended
               *
               * A custom error message can be given as the second argument to `expect`.
               *
               *     expect({}, 'nooo why fail??').to.be.arguments;
               *
               * The alias `.Arguments` can be used interchangeably with `.arguments`.
               *
               * @name arguments
               * @alias Arguments
               * @namespace BDD
               * @api public
               */
  
              function checkArguments() {
                var obj = flag(this, 'object'),
                  type = _.type(obj);
                this.assert(
                  'Arguments' === type,
                  'expected #{this} to be arguments but got ' + type,
                  'expected #{this} to not be arguments'
                );
              }
  
              Assertion.addProperty('arguments', checkArguments);
              Assertion.addProperty('Arguments', checkArguments);
  
              /**
               * ### .equal(val[, msg])
               *
               * Asserts that the target is strictly (`===`) equal to the given `val`.
               *
               *     expect(1).to.equal(1);
               *     expect('foo').to.equal('foo');
               *
               * Add `.deep` earlier in the chain to use deep equality instead. See the
               * `deep-eql` project page for info on the deep equality algorithm:
               * https://github.com/chaijs/deep-eql.
               *
               *     // Target object deeply (but not strictly) equals `{a: 1}`
               *     expect({a: 1}).to.deep.equal({a: 1});
               *     expect({a: 1}).to.not.equal({a: 1});
               *
               *     // Target array deeply (but not strictly) equals `[1, 2]`
               *     expect([1, 2]).to.deep.equal([1, 2]);
               *     expect([1, 2]).to.not.equal([1, 2]);
               *
               * Add `.not` earlier in the chain to negate `.equal`. However, it's often
               * best to assert that the target is equal to its expected value, rather than
               * not equal to one of countless unexpected values.
               *
               *     expect(1).to.equal(1); // Recommended
               *     expect(1).to.not.equal(2); // Not recommended
               *
               * `.equal` accepts an optional `msg` argument which is a custom error message
               * to show when the assertion fails. The message can also be given as the
               * second argument to `expect`.
               *
               *     expect(1).to.equal(2, 'nooo why fail??');
               *     expect(1, 'nooo why fail??').to.equal(2);
               *
               * The aliases `.equals` and `eq` can be used interchangeably with `.equal`.
               *
               * @name equal
               * @alias equals
               * @alias eq
               * @param {Mixed} val
               * @param {String} msg _optional_
               * @namespace BDD
               * @api public
               */
  
              function assertEqual(val, msg) {
                if (msg) flag(this, 'message', msg);
                var obj = flag(this, 'object');
                if (flag(this, 'deep')) {
                  var prevLockSsfi = flag(this, 'lockSsfi');
                  flag(this, 'lockSsfi', true);
                  this.eql(val);
                  flag(this, 'lockSsfi', prevLockSsfi);
                } else {
                  this.assert(
                    val === obj,
                    'expected #{this} to equal #{exp}',
                    'expected #{this} to not equal #{exp}',
                    val,
                    this._obj,
                    true
                  );
                }
              }
  
              Assertion.addMethod('equal', assertEqual);
              Assertion.addMethod('equals', assertEqual);
              Assertion.addMethod('eq', assertEqual);
  
              /**
               * ### .eql(obj[, msg])
               *
               * Asserts that the target is deeply equal to the given `obj`. See the
               * `deep-eql` project page for info on the deep equality algorithm:
               * https://github.com/chaijs/deep-eql.
               *
               *     // Target object is deeply (but not strictly) equal to {a: 1}
               *     expect({a: 1}).to.eql({a: 1}).but.not.equal({a: 1});
               *
               *     // Target array is deeply (but not strictly) equal to [1, 2]
               *     expect([1, 2]).to.eql([1, 2]).but.not.equal([1, 2]);
               *
               * Add `.not` earlier in the chain to negate `.eql`. However, it's often best
               * to assert that the target is deeply equal to its expected value, rather
               * than not deeply equal to one of countless unexpected values.
               *
               *     expect({a: 1}).to.eql({a: 1}); // Recommended
               *     expect({a: 1}).to.not.eql({b: 2}); // Not recommended
               *
               * `.eql` accepts an optional `msg` argument which is a custom error message
               * to show when the assertion fails. The message can also be given as the
               * second argument to `expect`.
               *
               *     expect({a: 1}).to.eql({b: 2}, 'nooo why fail??');
               *     expect({a: 1}, 'nooo why fail??').to.eql({b: 2});
               *
               * The alias `.eqls` can be used interchangeably with `.eql`.
               *
               * The `.deep.equal` assertion is almost identical to `.eql` but with one
               * difference: `.deep.equal` causes deep equality comparisons to also be used
               * for any other assertions that follow in the chain.
               *
               * @name eql
               * @alias eqls
               * @param {Mixed} obj
               * @param {String} msg _optional_
               * @namespace BDD
               * @api public
               */
  
              function assertEql(obj, msg) {
                if (msg) flag(this, 'message', msg);
                this.assert(
                  _.eql(obj, flag(this, 'object')),
                  'expected #{this} to deeply equal #{exp}',
                  'expected #{this} to not deeply equal #{exp}',
                  obj,
                  this._obj,
                  true
                );
              }
  
              Assertion.addMethod('eql', assertEql);
              Assertion.addMethod('eqls', assertEql);
  
              /**
               * ### .above(n[, msg])
               *
               * Asserts that the target is a number or a date greater than the given number or date `n` respectively.
               * However, it's often best to assert that the target is equal to its expected
               * value.
               *
               *     expect(2).to.equal(2); // Recommended
               *     expect(2).to.be.above(1); // Not recommended
               *
               * Add `.lengthOf` earlier in the chain to assert that the target's `length`
               * or `size` is greater than the given number `n`.
               *
               *     expect('foo').to.have.lengthOf(3); // Recommended
               *     expect('foo').to.have.lengthOf.above(2); // Not recommended
               *
               *     expect([1, 2, 3]).to.have.lengthOf(3); // Recommended
               *     expect([1, 2, 3]).to.have.lengthOf.above(2); // Not recommended
               *
               * Add `.not` earlier in the chain to negate `.above`.
               *
               *     expect(2).to.equal(2); // Recommended
               *     expect(1).to.not.be.above(2); // Not recommended
               *
               * `.above` accepts an optional `msg` argument which is a custom error message
               * to show when the assertion fails. The message can also be given as the
               * second argument to `expect`.
               *
               *     expect(1).to.be.above(2, 'nooo why fail??');
               *     expect(1, 'nooo why fail??').to.be.above(2);
               *
               * The aliases `.gt` and `.greaterThan` can be used interchangeably with
               * `.above`.
               *
               * @name above
               * @alias gt
               * @alias greaterThan
               * @param {Number} n
               * @param {String} msg _optional_
               * @namespace BDD
               * @api public
               */
  
              function assertAbove(n, msg) {
                if (msg) flag(this, 'message', msg);
                var obj = flag(this, 'object'),
                  doLength = flag(this, 'doLength'),
                  flagMsg = flag(this, 'message'),
                  msgPrefix = flagMsg ? flagMsg + ': ' : '',
                  ssfi = flag(this, 'ssfi'),
                  objType = _.type(obj).toLowerCase(),
                  nType = _.type(n).toLowerCase(),
                  errorMessage,
                  shouldThrow = true;
  
                if (doLength && objType !== 'map' && objType !== 'set') {
                  new Assertion(obj, flagMsg, ssfi, true).to.have.property('length');
                }
  
                if (!doLength && objType === 'date' && nType !== 'date') {
                  errorMessage = msgPrefix + 'the argument to above must be a date';
                } else if (nType !== 'number' && (doLength || objType === 'number')) {
                  errorMessage = msgPrefix + 'the argument to above must be a number';
                } else if (!doLength && objType !== 'date' && objType !== 'number') {
                  var printObj = objType === 'string' ? "'" + obj + "'" : obj;
                  errorMessage = msgPrefix + 'expected ' + printObj + ' to be a number or a date';
                } else {
                  shouldThrow = false;
                }
  
                if (shouldThrow) {
                  throw new AssertionError(errorMessage, undefined, ssfi);
                }
  
                if (doLength) {
                  var descriptor = 'length',
                    itemsCount;
                  if (objType === 'map' || objType === 'set') {
                    descriptor = 'size';
                    itemsCount = obj.size;
                  } else {
                    itemsCount = obj.length;
                  }
                  this.assert(
                    itemsCount > n,
                    'expected #{this} to have a ' + descriptor + ' above #{exp} but got #{act}',
                    'expected #{this} to not have a ' + descriptor + ' above #{exp}',
                    n,
                    itemsCount
                  );
                } else {
                  this.assert(
                    obj > n,
                    'expected #{this} to be above #{exp}',
                    'expected #{this} to be at most #{exp}',
                    n
                  );
                }
              }
  
              Assertion.addMethod('above', assertAbove);
              Assertion.addMethod('gt', assertAbove);
              Assertion.addMethod('greaterThan', assertAbove);
  
              /**
               * ### .least(n[, msg])
               *
               * Asserts that the target is a number or a date greater than or equal to the given
               * number or date `n` respectively. However, it's often best to assert that the target is equal to
               * its expected value.
               *
               *     expect(2).to.equal(2); // Recommended
               *     expect(2).to.be.at.least(1); // Not recommended
               *     expect(2).to.be.at.least(2); // Not recommended
               *
               * Add `.lengthOf` earlier in the chain to assert that the target's `length`
               * or `size` is greater than or equal to the given number `n`.
               *
               *     expect('foo').to.have.lengthOf(3); // Recommended
               *     expect('foo').to.have.lengthOf.at.least(2); // Not recommended
               *
               *     expect([1, 2, 3]).to.have.lengthOf(3); // Recommended
               *     expect([1, 2, 3]).to.have.lengthOf.at.least(2); // Not recommended
               *
               * Add `.not` earlier in the chain to negate `.least`.
               *
               *     expect(1).to.equal(1); // Recommended
               *     expect(1).to.not.be.at.least(2); // Not recommended
               *
               * `.least` accepts an optional `msg` argument which is a custom error message
               * to show when the assertion fails. The message can also be given as the
               * second argument to `expect`.
               *
               *     expect(1).to.be.at.least(2, 'nooo why fail??');
               *     expect(1, 'nooo why fail??').to.be.at.least(2);
               *
               * The alias `.gte` can be used interchangeably with `.least`.
               *
               * @name least
               * @alias gte
               * @param {Number} n
               * @param {String} msg _optional_
               * @namespace BDD
               * @api public
               */
  
              function assertLeast(n, msg) {
                if (msg) flag(this, 'message', msg);
                var obj = flag(this, 'object'),
                  doLength = flag(this, 'doLength'),
                  flagMsg = flag(this, 'message'),
                  msgPrefix = flagMsg ? flagMsg + ': ' : '',
                  ssfi = flag(this, 'ssfi'),
                  objType = _.type(obj).toLowerCase(),
                  nType = _.type(n).toLowerCase(),
                  errorMessage,
                  shouldThrow = true;
  
                if (doLength && objType !== 'map' && objType !== 'set') {
                  new Assertion(obj, flagMsg, ssfi, true).to.have.property('length');
                }
  
                if (!doLength && objType === 'date' && nType !== 'date') {
                  errorMessage = msgPrefix + 'the argument to least must be a date';
                } else if (nType !== 'number' && (doLength || objType === 'number')) {
                  errorMessage = msgPrefix + 'the argument to least must be a number';
                } else if (!doLength && objType !== 'date' && objType !== 'number') {
                  var printObj = objType === 'string' ? "'" + obj + "'" : obj;
                  errorMessage = msgPrefix + 'expected ' + printObj + ' to be a number or a date';
                } else {
                  shouldThrow = false;
                }
  
                if (shouldThrow) {
                  throw new AssertionError(errorMessage, undefined, ssfi);
                }
  
                if (doLength) {
                  var descriptor = 'length',
                    itemsCount;
                  if (objType === 'map' || objType === 'set') {
                    descriptor = 'size';
                    itemsCount = obj.size;
                  } else {
                    itemsCount = obj.length;
                  }
                  this.assert(
                    itemsCount >= n,
                    'expected #{this} to have a ' + descriptor + ' at least #{exp} but got #{act}',
                    'expected #{this} to have a ' + descriptor + ' below #{exp}',
                    n,
                    itemsCount
                  );
                } else {
                  this.assert(
                    obj >= n,
                    'expected #{this} to be at least #{exp}',
                    'expected #{this} to be below #{exp}',
                    n
                  );
                }
              }
  
              Assertion.addMethod('least', assertLeast);
              Assertion.addMethod('gte', assertLeast);
  
              /**
               * ### .below(n[, msg])
               *
               * Asserts that the target is a number or a date less than the given number or date `n` respectively.
               * However, it's often best to assert that the target is equal to its expected
               * value.
               *
               *     expect(1).to.equal(1); // Recommended
               *     expect(1).to.be.below(2); // Not recommended
               *
               * Add `.lengthOf` earlier in the chain to assert that the target's `length`
               * or `size` is less than the given number `n`.
               *
               *     expect('foo').to.have.lengthOf(3); // Recommended
               *     expect('foo').to.have.lengthOf.below(4); // Not recommended
               *
               *     expect([1, 2, 3]).to.have.length(3); // Recommended
               *     expect([1, 2, 3]).to.have.lengthOf.below(4); // Not recommended
               *
               * Add `.not` earlier in the chain to negate `.below`.
               *
               *     expect(2).to.equal(2); // Recommended
               *     expect(2).to.not.be.below(1); // Not recommended
               *
               * `.below` accepts an optional `msg` argument which is a custom error message
               * to show when the assertion fails. The message can also be given as the
               * second argument to `expect`.
               *
               *     expect(2).to.be.below(1, 'nooo why fail??');
               *     expect(2, 'nooo why fail??').to.be.below(1);
               *
               * The aliases `.lt` and `.lessThan` can be used interchangeably with
               * `.below`.
               *
               * @name below
               * @alias lt
               * @alias lessThan
               * @param {Number} n
               * @param {String} msg _optional_
               * @namespace BDD
               * @api public
               */
  
              function assertBelow(n, msg) {
                if (msg) flag(this, 'message', msg);
                var obj = flag(this, 'object'),
                  doLength = flag(this, 'doLength'),
                  flagMsg = flag(this, 'message'),
                  msgPrefix = flagMsg ? flagMsg + ': ' : '',
                  ssfi = flag(this, 'ssfi'),
                  objType = _.type(obj).toLowerCase(),
                  nType = _.type(n).toLowerCase(),
                  errorMessage,
                  shouldThrow = true;
  
                if (doLength && objType !== 'map' && objType !== 'set') {
                  new Assertion(obj, flagMsg, ssfi, true).to.have.property('length');
                }
  
                if (!doLength && objType === 'date' && nType !== 'date') {
                  errorMessage = msgPrefix + 'the argument to below must be a date';
                } else if (nType !== 'number' && (doLength || objType === 'number')) {
                  errorMessage = msgPrefix + 'the argument to below must be a number';
                } else if (!doLength && objType !== 'date' && objType !== 'number') {
                  var printObj = objType === 'string' ? "'" + obj + "'" : obj;
                  errorMessage = msgPrefix + 'expected ' + printObj + ' to be a number or a date';
                } else {
                  shouldThrow = false;
                }
  
                if (shouldThrow) {
                  throw new AssertionError(errorMessage, undefined, ssfi);
                }
  
                if (doLength) {
                  var descriptor = 'length',
                    itemsCount;
                  if (objType === 'map' || objType === 'set') {
                    descriptor = 'size';
                    itemsCount = obj.size;
                  } else {
                    itemsCount = obj.length;
                  }
                  this.assert(
                    itemsCount < n,
                    'expected #{this} to have a ' + descriptor + ' below #{exp} but got #{act}',
                    'expected #{this} to not have a ' + descriptor + ' below #{exp}',
                    n,
                    itemsCount
                  );
                } else {
                  this.assert(
                    obj < n,
                    'expected #{this} to be below #{exp}',
                    'expected #{this} to be at least #{exp}',
                    n
                  );
                }
              }
  
              Assertion.addMethod('below', assertBelow);
              Assertion.addMethod('lt', assertBelow);
              Assertion.addMethod('lessThan', assertBelow);
  
              /**
               * ### .most(n[, msg])
               *
               * Asserts that the target is a number or a date less than or equal to the given number
               * or date `n` respectively. However, it's often best to assert that the target is equal to its
               * expected value.
               *
               *     expect(1).to.equal(1); // Recommended
               *     expect(1).to.be.at.most(2); // Not recommended
               *     expect(1).to.be.at.most(1); // Not recommended
               *
               * Add `.lengthOf` earlier in the chain to assert that the target's `length`
               * or `size` is less than or equal to the given number `n`.
               *
               *     expect('foo').to.have.lengthOf(3); // Recommended
               *     expect('foo').to.have.lengthOf.at.most(4); // Not recommended
               *
               *     expect([1, 2, 3]).to.have.lengthOf(3); // Recommended
               *     expect([1, 2, 3]).to.have.lengthOf.at.most(4); // Not recommended
               *
               * Add `.not` earlier in the chain to negate `.most`.
               *
               *     expect(2).to.equal(2); // Recommended
               *     expect(2).to.not.be.at.most(1); // Not recommended
               *
               * `.most` accepts an optional `msg` argument which is a custom error message
               * to show when the assertion fails. The message can also be given as the
               * second argument to `expect`.
               *
               *     expect(2).to.be.at.most(1, 'nooo why fail??');
               *     expect(2, 'nooo why fail??').to.be.at.most(1);
               *
               * The alias `.lte` can be used interchangeably with `.most`.
               *
               * @name most
               * @alias lte
               * @param {Number} n
               * @param {String} msg _optional_
               * @namespace BDD
               * @api public
               */
  
              function assertMost(n, msg) {
                if (msg) flag(this, 'message', msg);
                var obj = flag(this, 'object'),
                  doLength = flag(this, 'doLength'),
                  flagMsg = flag(this, 'message'),
                  msgPrefix = flagMsg ? flagMsg + ': ' : '',
                  ssfi = flag(this, 'ssfi'),
                  objType = _.type(obj).toLowerCase(),
                  nType = _.type(n).toLowerCase(),
                  errorMessage,
                  shouldThrow = true;
  
                if (doLength && objType !== 'map' && objType !== 'set') {
                  new Assertion(obj, flagMsg, ssfi, true).to.have.property('length');
                }
  
                if (!doLength && objType === 'date' && nType !== 'date') {
                  errorMessage = msgPrefix + 'the argument to most must be a date';
                } else if (nType !== 'number' && (doLength || objType === 'number')) {
                  errorMessage = msgPrefix + 'the argument to most must be a number';
                } else if (!doLength && objType !== 'date' && objType !== 'number') {
                  var printObj = objType === 'string' ? "'" + obj + "'" : obj;
                  errorMessage = msgPrefix + 'expected ' + printObj + ' to be a number or a date';
                } else {
                  shouldThrow = false;
                }
  
                if (shouldThrow) {
                  throw new AssertionError(errorMessage, undefined, ssfi);
                }
  
                if (doLength) {
                  var descriptor = 'length',
                    itemsCount;
                  if (objType === 'map' || objType === 'set') {
                    descriptor = 'size';
                    itemsCount = obj.size;
                  } else {
                    itemsCount = obj.length;
                  }
                  this.assert(
                    itemsCount <= n,
                    'expected #{this} to have a ' + descriptor + ' at most #{exp} but got #{act}',
                    'expected #{this} to have a ' + descriptor + ' above #{exp}',
                    n,
                    itemsCount
                  );
                } else {
                  this.assert(
                    obj <= n,
                    'expected #{this} to be at most #{exp}',
                    'expected #{this} to be above #{exp}',
                    n
                  );
                }
              }
  
              Assertion.addMethod('most', assertMost);
              Assertion.addMethod('lte', assertMost);
  
              /**
               * ### .within(start, finish[, msg])
               *
               * Asserts that the target is a number or a date greater than or equal to the given
               * number or date `start`, and less than or equal to the given number or date `finish` respectively.
               * However, it's often best to assert that the target is equal to its expected
               * value.
               *
               *     expect(2).to.equal(2); // Recommended
               *     expect(2).to.be.within(1, 3); // Not recommended
               *     expect(2).to.be.within(2, 3); // Not recommended
               *     expect(2).to.be.within(1, 2); // Not recommended
               *
               * Add `.lengthOf` earlier in the chain to assert that the target's `length`
               * or `size` is greater than or equal to the given number `start`, and less
               * than or equal to the given number `finish`.
               *
               *     expect('foo').to.have.lengthOf(3); // Recommended
               *     expect('foo').to.have.lengthOf.within(2, 4); // Not recommended
               *
               *     expect([1, 2, 3]).to.have.lengthOf(3); // Recommended
               *     expect([1, 2, 3]).to.have.lengthOf.within(2, 4); // Not recommended
               *
               * Add `.not` earlier in the chain to negate `.within`.
               *
               *     expect(1).to.equal(1); // Recommended
               *     expect(1).to.not.be.within(2, 4); // Not recommended
               *
               * `.within` accepts an optional `msg` argument which is a custom error
               * message to show when the assertion fails. The message can also be given as
               * the second argument to `expect`.
               *
               *     expect(4).to.be.within(1, 3, 'nooo why fail??');
               *     expect(4, 'nooo why fail??').to.be.within(1, 3);
               *
               * @name within
               * @param {Number} start lower bound inclusive
               * @param {Number} finish upper bound inclusive
               * @param {String} msg _optional_
               * @namespace BDD
               * @api public
               */
  
              Assertion.addMethod('within', function (start, finish, msg) {
                if (msg) flag(this, 'message', msg);
                var obj = flag(this, 'object'),
                  doLength = flag(this, 'doLength'),
                  flagMsg = flag(this, 'message'),
                  msgPrefix = flagMsg ? flagMsg + ': ' : '',
                  ssfi = flag(this, 'ssfi'),
                  objType = _.type(obj).toLowerCase(),
                  startType = _.type(start).toLowerCase(),
                  finishType = _.type(finish).toLowerCase(),
                  errorMessage,
                  shouldThrow = true,
                  range =
                    startType === 'date' && finishType === 'date'
                      ? start.toUTCString() + '..' + finish.toUTCString()
                      : start + '..' + finish;
  
                if (doLength && objType !== 'map' && objType !== 'set') {
                  new Assertion(obj, flagMsg, ssfi, true).to.have.property('length');
                }
  
                if (
                  !doLength &&
                  objType === 'date' &&
                  (startType !== 'date' || finishType !== 'date')
                ) {
                  errorMessage = msgPrefix + 'the arguments to within must be dates';
                } else if (
                  (startType !== 'number' || finishType !== 'number') &&
                  (doLength || objType === 'number')
                ) {
                  errorMessage = msgPrefix + 'the arguments to within must be numbers';
                } else if (!doLength && objType !== 'date' && objType !== 'number') {
                  var printObj = objType === 'string' ? "'" + obj + "'" : obj;
                  errorMessage = msgPrefix + 'expected ' + printObj + ' to be a number or a date';
                } else {
                  shouldThrow = false;
                }
  
                if (shouldThrow) {
                  throw new AssertionError(errorMessage, undefined, ssfi);
                }
  
                if (doLength) {
                  var descriptor = 'length',
                    itemsCount;
                  if (objType === 'map' || objType === 'set') {
                    descriptor = 'size';
                    itemsCount = obj.size;
                  } else {
                    itemsCount = obj.length;
                  }
                  this.assert(
                    itemsCount >= start && itemsCount <= finish,
                    'expected #{this} to have a ' + descriptor + ' within ' + range,
                    'expected #{this} to not have a ' + descriptor + ' within ' + range
                  );
                } else {
                  this.assert(
                    obj >= start && obj <= finish,
                    'expected #{this} to be within ' + range,
                    'expected #{this} to not be within ' + range
                  );
                }
              });
  
              /**
               * ### .instanceof(constructor[, msg])
               *
               * Asserts that the target is an instance of the given `constructor`.
               *
               *     function Cat () { }
               *
               *     expect(new Cat()).to.be.an.instanceof(Cat);
               *     expect([1, 2]).to.be.an.instanceof(Array);
               *
               * Add `.not` earlier in the chain to negate `.instanceof`.
               *
               *     expect({a: 1}).to.not.be.an.instanceof(Array);
               *
               * `.instanceof` accepts an optional `msg` argument which is a custom error
               * message to show when the assertion fails. The message can also be given as
               * the second argument to `expect`.
               *
               *     expect(1).to.be.an.instanceof(Array, 'nooo why fail??');
               *     expect(1, 'nooo why fail??').to.be.an.instanceof(Array);
               *
               * Due to limitations in ES5, `.instanceof` may not always work as expected
               * when using a transpiler such as Babel or TypeScript. In particular, it may
               * produce unexpected results when subclassing built-in object such as
               * `Array`, `Error`, and `Map`. See your transpiler's docs for details:
               *
               * - ([Babel](https://babeljs.io/docs/usage/caveats/#classes))
               * - ([TypeScript](https://github.com/Microsoft/TypeScript/wiki/Breaking-Changes#extending-built-ins-like-error-array-and-map-may-no-longer-work))
               *
               * The alias `.instanceOf` can be used interchangeably with `.instanceof`.
               *
               * @name instanceof
               * @param {Constructor} constructor
               * @param {String} msg _optional_
               * @alias instanceOf
               * @namespace BDD
               * @api public
               */
  
              function assertInstanceOf(constructor, msg) {
                if (msg) flag(this, 'message', msg);
  
                var target = flag(this, 'object');
                var ssfi = flag(this, 'ssfi');
                var flagMsg = flag(this, 'message');
  
                try {
                  var isInstanceOf = target instanceof constructor;
                } catch (err) {
                  if (err instanceof TypeError) {
                    flagMsg = flagMsg ? flagMsg + ': ' : '';
                    throw new AssertionError(
                      flagMsg +
                        'The instanceof assertion needs a constructor but ' +
                        _.type(constructor) +
                        ' was given.',
                      undefined,
                      ssfi
                    );
                  }
                  throw err;
                }
  
                var name = _.getName(constructor);
                if (name === null) {
                  name = 'an unnamed constructor';
                }
  
                this.assert(
                  isInstanceOf,
                  'expected #{this} to be an instance of ' + name,
                  'expected #{this} to not be an instance of ' + name
                );
              }
  
              Assertion.addMethod('instanceof', assertInstanceOf);
              Assertion.addMethod('instanceOf', assertInstanceOf);
  
              /**
               * ### .property(name[, val[, msg]])
               *
               * Asserts that the target has a property with the given key `name`.
               *
               *     expect({a: 1}).to.have.property('a');
               *
               * When `val` is provided, `.property` also asserts that the property's value
               * is equal to the given `val`.
               *
               *     expect({a: 1}).to.have.property('a', 1);
               *
               * By default, strict (`===`) equality is used. Add `.deep` earlier in the
               * chain to use deep equality instead. See the `deep-eql` project page for
               * info on the deep equality algorithm: https://github.com/chaijs/deep-eql.
               *
               *     // Target object deeply (but not strictly) has property `x: {a: 1}`
               *     expect({x: {a: 1}}).to.have.deep.property('x', {a: 1});
               *     expect({x: {a: 1}}).to.not.have.property('x', {a: 1});
               *
               * The target's enumerable and non-enumerable properties are always included
               * in the search. By default, both own and inherited properties are included.
               * Add `.own` earlier in the chain to exclude inherited properties from the
               * search.
               *
               *     Object.prototype.b = 2;
               *
               *     expect({a: 1}).to.have.own.property('a');
               *     expect({a: 1}).to.have.own.property('a', 1);
               *     expect({a: 1}).to.have.property('b');
               *     expect({a: 1}).to.not.have.own.property('b');
               *
               * `.deep` and `.own` can be combined.
               *
               *     expect({x: {a: 1}}).to.have.deep.own.property('x', {a: 1});
               *
               * Add `.nested` earlier in the chain to enable dot- and bracket-notation when
               * referencing nested properties.
               *
               *     expect({a: {b: ['x', 'y']}}).to.have.nested.property('a.b[1]');
               *     expect({a: {b: ['x', 'y']}}).to.have.nested.property('a.b[1]', 'y');
               *
               * If `.` or `[]` are part of an actual property name, they can be escaped by
               * adding two backslashes before them.
               *
               *     expect({'.a': {'[b]': 'x'}}).to.have.nested.property('\\.a.\\[b\\]');
               *
               * `.deep` and `.nested` can be combined.
               *
               *     expect({a: {b: [{c: 3}]}})
               *       .to.have.deep.nested.property('a.b[0]', {c: 3});
               *
               * `.own` and `.nested` cannot be combined.
               *
               * Add `.not` earlier in the chain to negate `.property`.
               *
               *     expect({a: 1}).to.not.have.property('b');
               *
               * However, it's dangerous to negate `.property` when providing `val`. The
               * problem is that it creates uncertain expectations by asserting that the
               * target either doesn't have a property with the given key `name`, or that it
               * does have a property with the given key `name` but its value isn't equal to
               * the given `val`. It's often best to identify the exact output that's
               * expected, and then write an assertion that only accepts that exact output.
               *
               * When the target isn't expected to have a property with the given key
               * `name`, it's often best to assert exactly that.
               *
               *     expect({b: 2}).to.not.have.property('a'); // Recommended
               *     expect({b: 2}).to.not.have.property('a', 1); // Not recommended
               *
               * When the target is expected to have a property with the given key `name`,
               * it's often best to assert that the property has its expected value, rather
               * than asserting that it doesn't have one of many unexpected values.
               *
               *     expect({a: 3}).to.have.property('a', 3); // Recommended
               *     expect({a: 3}).to.not.have.property('a', 1); // Not recommended
               *
               * `.property` changes the target of any assertions that follow in the chain
               * to be the value of the property from the original target object.
               *
               *     expect({a: 1}).to.have.property('a').that.is.a('number');
               *
               * `.property` accepts an optional `msg` argument which is a custom error
               * message to show when the assertion fails. The message can also be given as
               * the second argument to `expect`. When not providing `val`, only use the
               * second form.
               *
               *     // Recommended
               *     expect({a: 1}).to.have.property('a', 2, 'nooo why fail??');
               *     expect({a: 1}, 'nooo why fail??').to.have.property('a', 2);
               *     expect({a: 1}, 'nooo why fail??').to.have.property('b');
               *
               *     // Not recommended
               *     expect({a: 1}).to.have.property('b', undefined, 'nooo why fail??');
               *
               * The above assertion isn't the same thing as not providing `val`. Instead,
               * it's asserting that the target object has a `b` property that's equal to
               * `undefined`.
               *
               * The assertions `.ownProperty` and `.haveOwnProperty` can be used
               * interchangeably with `.own.property`.
               *
               * @name property
               * @param {String} name
               * @param {Mixed} val (optional)
               * @param {String} msg _optional_
               * @returns value of property for chaining
               * @namespace BDD
               * @api public
               */
  
              function assertProperty(name, val, msg) {
                if (msg) flag(this, 'message', msg);
  
                var isNested = flag(this, 'nested'),
                  isOwn = flag(this, 'own'),
                  flagMsg = flag(this, 'message'),
                  obj = flag(this, 'object'),
                  ssfi = flag(this, 'ssfi'),
                  nameType = typeof name;
  
                flagMsg = flagMsg ? flagMsg + ': ' : '';
  
                if (isNested) {
                  if (nameType !== 'string') {
                    throw new AssertionError(
                      flagMsg + 'the argument to property must be a string when using nested syntax',
                      undefined,
                      ssfi
                    );
                  }
                } else {
                  if (nameType !== 'string' && nameType !== 'number' && nameType !== 'symbol') {
                    throw new AssertionError(
                      flagMsg + 'the argument to property must be a string, number, or symbol',
                      undefined,
                      ssfi
                    );
                  }
                }
  
                if (isNested && isOwn) {
                  throw new AssertionError(
                    flagMsg + 'The "nested" and "own" flags cannot be combined.',
                    undefined,
                    ssfi
                  );
                }
  
                if (obj === null || obj === undefined) {
                  throw new AssertionError(
                    flagMsg + 'Target cannot be null or undefined.',
                    undefined,
                    ssfi
                  );
                }
  
                var isDeep = flag(this, 'deep'),
                  negate = flag(this, 'negate'),
                  pathInfo = isNested ? _.getPathInfo(obj, name) : null,
                  value = isNested ? pathInfo.value : obj[name];
  
                var descriptor = '';
                if (isDeep) descriptor += 'deep ';
                if (isOwn) descriptor += 'own ';
                if (isNested) descriptor += 'nested ';
                descriptor += 'property ';
  
                var hasProperty;
                if (isOwn) hasProperty = Object.prototype.hasOwnProperty.call(obj, name);
                else if (isNested) hasProperty = pathInfo.exists;
                else hasProperty = _.hasProperty(obj, name);
  
                // When performing a negated assertion for both name and val, merely having
                // a property with the given name isn't enough to cause the assertion to
                // fail. It must both have a property with the given name, and the value of
                // that property must equal the given val. Therefore, skip this assertion in
                // favor of the next.
                if (!negate || arguments.length === 1) {
                  this.assert(
                    hasProperty,
                    'expected #{this} to have ' + descriptor + _.inspect(name),
                    'expected #{this} to not have ' + descriptor + _.inspect(name)
                  );
                }
  
                if (arguments.length > 1) {
                  this.assert(
                    hasProperty && (isDeep ? _.eql(val, value) : val === value),
                    'expected #{this} to have ' +
                      descriptor +
                      _.inspect(name) +
                      ' of #{exp}, but got #{act}',
                    'expected #{this} to not have ' + descriptor + _.inspect(name) + ' of #{act}',
                    val,
                    value
                  );
                }
  
                flag(this, 'object', value);
              }
  
              Assertion.addMethod('property', assertProperty);
  
              function assertOwnProperty(name, value, msg) {
                flag(this, 'own', true);
                assertProperty.apply(this, arguments);
              }
  
              Assertion.addMethod('ownProperty', assertOwnProperty);
              Assertion.addMethod('haveOwnProperty', assertOwnProperty);
  
              /**
               * ### .ownPropertyDescriptor(name[, descriptor[, msg]])
               *
               * Asserts that the target has its own property descriptor with the given key
               * `name`. Enumerable and non-enumerable properties are included in the
               * search.
               *
               *     expect({a: 1}).to.have.ownPropertyDescriptor('a');
               *
               * When `descriptor` is provided, `.ownPropertyDescriptor` also asserts that
               * the property's descriptor is deeply equal to the given `descriptor`. See
               * the `deep-eql` project page for info on the deep equality algorithm:
               * https://github.com/chaijs/deep-eql.
               *
               *     expect({a: 1}).to.have.ownPropertyDescriptor('a', {
               *       configurable: true,
               *       enumerable: true,
               *       writable: true,
               *       value: 1,
               *     });
               *
               * Add `.not` earlier in the chain to negate `.ownPropertyDescriptor`.
               *
               *     expect({a: 1}).to.not.have.ownPropertyDescriptor('b');
               *
               * However, it's dangerous to negate `.ownPropertyDescriptor` when providing
               * a `descriptor`. The problem is that it creates uncertain expectations by
               * asserting that the target either doesn't have a property descriptor with
               * the given key `name`, or that it does have a property descriptor with the
               * given key `name` but its not deeply equal to the given `descriptor`. It's
               * often best to identify the exact output that's expected, and then write an
               * assertion that only accepts that exact output.
               *
               * When the target isn't expected to have a property descriptor with the given
               * key `name`, it's often best to assert exactly that.
               *
               *     // Recommended
               *     expect({b: 2}).to.not.have.ownPropertyDescriptor('a');
               *
               *     // Not recommended
               *     expect({b: 2}).to.not.have.ownPropertyDescriptor('a', {
               *       configurable: true,
               *       enumerable: true,
               *       writable: true,
               *       value: 1,
               *     });
               *
               * When the target is expected to have a property descriptor with the given
               * key `name`, it's often best to assert that the property has its expected
               * descriptor, rather than asserting that it doesn't have one of many
               * unexpected descriptors.
               *
               *     // Recommended
               *     expect({a: 3}).to.have.ownPropertyDescriptor('a', {
               *       configurable: true,
               *       enumerable: true,
               *       writable: true,
               *       value: 3,
               *     });
               *
               *     // Not recommended
               *     expect({a: 3}).to.not.have.ownPropertyDescriptor('a', {
               *       configurable: true,
               *       enumerable: true,
               *       writable: true,
               *       value: 1,
               *     });
               *
               * `.ownPropertyDescriptor` changes the target of any assertions that follow
               * in the chain to be the value of the property descriptor from the original
               * target object.
               *
               *     expect({a: 1}).to.have.ownPropertyDescriptor('a')
               *       .that.has.property('enumerable', true);
               *
               * `.ownPropertyDescriptor` accepts an optional `msg` argument which is a
               * custom error message to show when the assertion fails. The message can also
               * be given as the second argument to `expect`. When not providing
               * `descriptor`, only use the second form.
               *
               *     // Recommended
               *     expect({a: 1}).to.have.ownPropertyDescriptor('a', {
               *       configurable: true,
               *       enumerable: true,
               *       writable: true,
               *       value: 2,
               *     }, 'nooo why fail??');
               *
               *     // Recommended
               *     expect({a: 1}, 'nooo why fail??').to.have.ownPropertyDescriptor('a', {
               *       configurable: true,
               *       enumerable: true,
               *       writable: true,
               *       value: 2,
               *     });
               *
               *     // Recommended
               *     expect({a: 1}, 'nooo why fail??').to.have.ownPropertyDescriptor('b');
               *
               *     // Not recommended
               *     expect({a: 1})
               *       .to.have.ownPropertyDescriptor('b', undefined, 'nooo why fail??');
               *
               * The above assertion isn't the same thing as not providing `descriptor`.
               * Instead, it's asserting that the target object has a `b` property
               * descriptor that's deeply equal to `undefined`.
               *
               * The alias `.haveOwnPropertyDescriptor` can be used interchangeably with
               * `.ownPropertyDescriptor`.
               *
               * @name ownPropertyDescriptor
               * @alias haveOwnPropertyDescriptor
               * @param {String} name
               * @param {Object} descriptor _optional_
               * @param {String} msg _optional_
               * @namespace BDD
               * @api public
               */
  
              function assertOwnPropertyDescriptor(name, descriptor, msg) {
                if (typeof descriptor === 'string') {
                  msg = descriptor;
                  descriptor = null;
                }
                if (msg) flag(this, 'message', msg);
                var obj = flag(this, 'object');
                var actualDescriptor = Object.getOwnPropertyDescriptor(Object(obj), name);
                if (actualDescriptor && descriptor) {
                  this.assert(
                    _.eql(descriptor, actualDescriptor),
                    'expected the own property descriptor for ' +
                      _.inspect(name) +
                      ' on #{this} to match ' +
                      _.inspect(descriptor) +
                      ', got ' +
                      _.inspect(actualDescriptor),
                    'expected the own property descriptor for ' +
                      _.inspect(name) +
                      ' on #{this} to not match ' +
                      _.inspect(descriptor),
                    descriptor,
                    actualDescriptor,
                    true
                  );
                } else {
                  this.assert(
                    actualDescriptor,
                    'expected #{this} to have an own property descriptor for ' + _.inspect(name),
                    'expected #{this} to not have an own property descriptor for ' + _.inspect(name)
                  );
                }
                flag(this, 'object', actualDescriptor);
              }
  
              Assertion.addMethod('ownPropertyDescriptor', assertOwnPropertyDescriptor);
              Assertion.addMethod('haveOwnPropertyDescriptor', assertOwnPropertyDescriptor);
  
              /**
               * ### .lengthOf(n[, msg])
               *
               * Asserts that the target's `length` or `size` is equal to the given number
               * `n`.
               *
               *     expect([1, 2, 3]).to.have.lengthOf(3);
               *     expect('foo').to.have.lengthOf(3);
               *     expect(new Set([1, 2, 3])).to.have.lengthOf(3);
               *     expect(new Map([['a', 1], ['b', 2], ['c', 3]])).to.have.lengthOf(3);
               *
               * Add `.not` earlier in the chain to negate `.lengthOf`. However, it's often
               * best to assert that the target's `length` property is equal to its expected
               * value, rather than not equal to one of many unexpected values.
               *
               *     expect('foo').to.have.lengthOf(3); // Recommended
               *     expect('foo').to.not.have.lengthOf(4); // Not recommended
               *
               * `.lengthOf` accepts an optional `msg` argument which is a custom error
               * message to show when the assertion fails. The message can also be given as
               * the second argument to `expect`.
               *
               *     expect([1, 2, 3]).to.have.lengthOf(2, 'nooo why fail??');
               *     expect([1, 2, 3], 'nooo why fail??').to.have.lengthOf(2);
               *
               * `.lengthOf` can also be used as a language chain, causing all `.above`,
               * `.below`, `.least`, `.most`, and `.within` assertions that follow in the
               * chain to use the target's `length` property as the target. However, it's
               * often best to assert that the target's `length` property is equal to its
               * expected length, rather than asserting that its `length` property falls
               * within some range of values.
               *
               *     // Recommended
               *     expect([1, 2, 3]).to.have.lengthOf(3);
               *
               *     // Not recommended
               *     expect([1, 2, 3]).to.have.lengthOf.above(2);
               *     expect([1, 2, 3]).to.have.lengthOf.below(4);
               *     expect([1, 2, 3]).to.have.lengthOf.at.least(3);
               *     expect([1, 2, 3]).to.have.lengthOf.at.most(3);
               *     expect([1, 2, 3]).to.have.lengthOf.within(2,4);
               *
               * Due to a compatibility issue, the alias `.length` can't be chained directly
               * off of an uninvoked method such as `.a`. Therefore, `.length` can't be used
               * interchangeably with `.lengthOf` in every situation. It's recommended to
               * always use `.lengthOf` instead of `.length`.
               *
               *     expect([1, 2, 3]).to.have.a.length(3); // incompatible; throws error
               *     expect([1, 2, 3]).to.have.a.lengthOf(3);  // passes as expected
               *
               * @name lengthOf
               * @alias length
               * @param {Number} n
               * @param {String} msg _optional_
               * @namespace BDD
               * @api public
               */
  
              function assertLengthChain() {
                flag(this, 'doLength', true);
              }
  
              function assertLength(n, msg) {
                if (msg) flag(this, 'message', msg);
                var obj = flag(this, 'object'),
                  objType = _.type(obj).toLowerCase(),
                  flagMsg = flag(this, 'message'),
                  ssfi = flag(this, 'ssfi'),
                  descriptor = 'length',
                  itemsCount;
  
                switch (objType) {
                  case 'map':
                  case 'set':
                    descriptor = 'size';
                    itemsCount = obj.size;
                    break;
                  default:
                    new Assertion(obj, flagMsg, ssfi, true).to.have.property('length');
                    itemsCount = obj.length;
                }
  
                this.assert(
                  itemsCount == n,
                  'expected #{this} to have a ' + descriptor + ' of #{exp} but got #{act}',
                  'expected #{this} to not have a ' + descriptor + ' of #{act}',
                  n,
                  itemsCount
                );
              }
  
              Assertion.addChainableMethod('length', assertLength, assertLengthChain);
              Assertion.addChainableMethod('lengthOf', assertLength, assertLengthChain);
  
              /**
               * ### .match(re[, msg])
               *
               * Asserts that the target matches the given regular expression `re`.
               *
               *     expect('foobar').to.match(/^foo/);
               *
               * Add `.not` earlier in the chain to negate `.match`.
               *
               *     expect('foobar').to.not.match(/taco/);
               *
               * `.match` accepts an optional `msg` argument which is a custom error message
               * to show when the assertion fails. The message can also be given as the
               * second argument to `expect`.
               *
               *     expect('foobar').to.match(/taco/, 'nooo why fail??');
               *     expect('foobar', 'nooo why fail??').to.match(/taco/);
               *
               * The alias `.matches` can be used interchangeably with `.match`.
               *
               * @name match
               * @alias matches
               * @param {RegExp} re
               * @param {String} msg _optional_
               * @namespace BDD
               * @api public
               */
              function assertMatch(re, msg) {
                if (msg) flag(this, 'message', msg);
                var obj = flag(this, 'object');
                this.assert(
                  re.exec(obj),
                  'expected #{this} to match ' + re,
                  'expected #{this} not to match ' + re
                );
              }
  
              Assertion.addMethod('match', assertMatch);
              Assertion.addMethod('matches', assertMatch);
  
              /**
               * ### .string(str[, msg])
               *
               * Asserts that the target string contains the given substring `str`.
               *
               *     expect('foobar').to.have.string('bar');
               *
               * Add `.not` earlier in the chain to negate `.string`.
               *
               *     expect('foobar').to.not.have.string('taco');
               *
               * `.string` accepts an optional `msg` argument which is a custom error
               * message to show when the assertion fails. The message can also be given as
               * the second argument to `expect`.
               *
               *     expect('foobar').to.have.string('taco', 'nooo why fail??');
               *     expect('foobar', 'nooo why fail??').to.have.string('taco');
               *
               * @name string
               * @param {String} str
               * @param {String} msg _optional_
               * @namespace BDD
               * @api public
               */
  
              Assertion.addMethod('string', function (str, msg) {
                if (msg) flag(this, 'message', msg);
                var obj = flag(this, 'object'),
                  flagMsg = flag(this, 'message'),
                  ssfi = flag(this, 'ssfi');
                new Assertion(obj, flagMsg, ssfi, true).is.a('string');
  
                this.assert(
                  ~obj.indexOf(str),
                  'expected #{this} to contain ' + _.inspect(str),
                  'expected #{this} to not contain ' + _.inspect(str)
                );
              });
  
              /**
               * ### .keys(key1[, key2[, ...]])
               *
               * Asserts that the target object, array, map, or set has the given keys. Only
               * the target's own inherited properties are included in the search.
               *
               * When the target is an object or array, keys can be provided as one or more
               * string arguments, a single array argument, or a single object argument. In
               * the latter case, only the keys in the given object matter; the values are
               * ignored.
               *
               *     expect({a: 1, b: 2}).to.have.all.keys('a', 'b');
               *     expect(['x', 'y']).to.have.all.keys(0, 1);
               *
               *     expect({a: 1, b: 2}).to.have.all.keys(['a', 'b']);
               *     expect(['x', 'y']).to.have.all.keys([0, 1]);
               *
               *     expect({a: 1, b: 2}).to.have.all.keys({a: 4, b: 5}); // ignore 4 and 5
               *     expect(['x', 'y']).to.have.all.keys({0: 4, 1: 5}); // ignore 4 and 5
               *
               * When the target is a map or set, each key must be provided as a separate
               * argument.
               *
               *     expect(new Map([['a', 1], ['b', 2]])).to.have.all.keys('a', 'b');
               *     expect(new Set(['a', 'b'])).to.have.all.keys('a', 'b');
               *
               * Because `.keys` does different things based on the target's type, it's
               * important to check the target's type before using `.keys`. See the `.a` doc
               * for info on testing a target's type.
               *
               *     expect({a: 1, b: 2}).to.be.an('object').that.has.all.keys('a', 'b');
               *
               * By default, strict (`===`) equality is used to compare keys of maps and
               * sets. Add `.deep` earlier in the chain to use deep equality instead. See
               * the `deep-eql` project page for info on the deep equality algorithm:
               * https://github.com/chaijs/deep-eql.
               *
               *     // Target set deeply (but not strictly) has key `{a: 1}`
               *     expect(new Set([{a: 1}])).to.have.all.deep.keys([{a: 1}]);
               *     expect(new Set([{a: 1}])).to.not.have.all.keys([{a: 1}]);
               *
               * By default, the target must have all of the given keys and no more. Add
               * `.any` earlier in the chain to only require that the target have at least
               * one of the given keys. Also, add `.not` earlier in the chain to negate
               * `.keys`. It's often best to add `.any` when negating `.keys`, and to use
               * `.all` when asserting `.keys` without negation.
               *
               * When negating `.keys`, `.any` is preferred because `.not.any.keys` asserts
               * exactly what's expected of the output, whereas `.not.all.keys` creates
               * uncertain expectations.
               *
               *     // Recommended; asserts that target doesn't have any of the given keys
               *     expect({a: 1, b: 2}).to.not.have.any.keys('c', 'd');
               *
               *     // Not recommended; asserts that target doesn't have all of the given
               *     // keys but may or may not have some of them
               *     expect({a: 1, b: 2}).to.not.have.all.keys('c', 'd');
               *
               * When asserting `.keys` without negation, `.all` is preferred because
               * `.all.keys` asserts exactly what's expected of the output, whereas
               * `.any.keys` creates uncertain expectations.
               *
               *     // Recommended; asserts that target has all the given keys
               *     expect({a: 1, b: 2}).to.have.all.keys('a', 'b');
               *
               *     // Not recommended; asserts that target has at least one of the given
               *     // keys but may or may not have more of them
               *     expect({a: 1, b: 2}).to.have.any.keys('a', 'b');
               *
               * Note that `.all` is used by default when neither `.all` nor `.any` appear
               * earlier in the chain. However, it's often best to add `.all` anyway because
               * it improves readability.
               *
               *     // Both assertions are identical
               *     expect({a: 1, b: 2}).to.have.all.keys('a', 'b'); // Recommended
               *     expect({a: 1, b: 2}).to.have.keys('a', 'b'); // Not recommended
               *
               * Add `.include` earlier in the chain to require that the target's keys be a
               * superset of the expected keys, rather than identical sets.
               *
               *     // Target object's keys are a superset of ['a', 'b'] but not identical
               *     expect({a: 1, b: 2, c: 3}).to.include.all.keys('a', 'b');
               *     expect({a: 1, b: 2, c: 3}).to.not.have.all.keys('a', 'b');
               *
               * However, if `.any` and `.include` are combined, only the `.any` takes
               * effect. The `.include` is ignored in this case.
               *
               *     // Both assertions are identical
               *     expect({a: 1}).to.have.any.keys('a', 'b');
               *     expect({a: 1}).to.include.any.keys('a', 'b');
               *
               * A custom error message can be given as the second argument to `expect`.
               *
               *     expect({a: 1}, 'nooo why fail??').to.have.key('b');
               *
               * The alias `.key` can be used interchangeably with `.keys`.
               *
               * @name keys
               * @alias key
               * @param {...String|Array|Object} keys
               * @namespace BDD
               * @api public
               */
  
              function assertKeys(keys) {
                var obj = flag(this, 'object'),
                  objType = _.type(obj),
                  keysType = _.type(keys),
                  ssfi = flag(this, 'ssfi'),
                  isDeep = flag(this, 'deep'),
                  str,
                  deepStr = '',
                  actual,
                  ok = true,
                  flagMsg = flag(this, 'message');
  
                flagMsg = flagMsg ? flagMsg + ': ' : '';
                var mixedArgsMsg =
                  flagMsg +
                  'when testing keys against an object or an array you must give a single Array|Object|String argument or multiple String arguments';
  
                if (objType === 'Map' || objType === 'Set') {
                  deepStr = isDeep ? 'deeply ' : '';
                  actual = [];
  
                  // Map and Set '.keys' aren't supported in IE 11. Therefore, use .forEach.
                  obj.forEach(function (val, key) {
                    actual.push(key);
                  });
  
                  if (keysType !== 'Array') {
                    keys = Array.prototype.slice.call(arguments);
                  }
                } else {
                  actual = _.getOwnEnumerableProperties(obj);
  
                  switch (keysType) {
                    case 'Array':
                      if (arguments.length > 1) {
                        throw new AssertionError(mixedArgsMsg, undefined, ssfi);
                      }
                      break;
                    case 'Object':
                      if (arguments.length > 1) {
                        throw new AssertionError(mixedArgsMsg, undefined, ssfi);
                      }
                      keys = Object.keys(keys);
                      break;
                    default:
                      keys = Array.prototype.slice.call(arguments);
                  }
  
                  // Only stringify non-Symbols because Symbols would become "Symbol()"
                  keys = keys.map(function (val) {
                    return typeof val === 'symbol' ? val : String(val);
                  });
                }
  
                if (!keys.length) {
                  throw new AssertionError(flagMsg + 'keys required', undefined, ssfi);
                }
  
                var len = keys.length,
                  any = flag(this, 'any'),
                  all = flag(this, 'all'),
                  expected = keys;
  
                if (!any && !all) {
                  all = true;
                }
  
                // Has any
                if (any) {
                  ok = expected.some(function (expectedKey) {
                    return actual.some(function (actualKey) {
                      if (isDeep) {
                        return _.eql(expectedKey, actualKey);
                      } else {
                        return expectedKey === actualKey;
                      }
                    });
                  });
                }
  
                // Has all
                if (all) {
                  ok = expected.every(function (expectedKey) {
                    return actual.some(function (actualKey) {
                      if (isDeep) {
                        return _.eql(expectedKey, actualKey);
                      } else {
                        return expectedKey === actualKey;
                      }
                    });
                  });
  
                  if (!flag(this, 'contains')) {
                    ok = ok && keys.length == actual.length;
                  }
                }
  
                // Key string
                if (len > 1) {
                  keys = keys.map(function (key) {
                    return _.inspect(key);
                  });
                  var last = keys.pop();
                  if (all) {
                    str = keys.join(', ') + ', and ' + last;
                  }
                  if (any) {
                    str = keys.join(', ') + ', or ' + last;
                  }
                } else {
                  str = _.inspect(keys[0]);
                }
  
                // Form
                str = (len > 1 ? 'keys ' : 'key ') + str;
  
                // Have / include
                str = (flag(this, 'contains') ? 'contain ' : 'have ') + str;
  
                // Assertion
                this.assert(
                  ok,
                  'expected #{this} to ' + deepStr + str,
                  'expected #{this} to not ' + deepStr + str,
                  expected.slice(0).sort(_.compareByInspect),
                  actual.sort(_.compareByInspect),
                  true
                );
              }
  
              Assertion.addMethod('keys', assertKeys);
              Assertion.addMethod('key', assertKeys);
  
              /**
               * ### .throw([errorLike], [errMsgMatcher], [msg])
               *
               * When no arguments are provided, `.throw` invokes the target function and
               * asserts that an error is thrown.
               *
               *     var badFn = function () { throw new TypeError('Illegal salmon!'); };
               *
               *     expect(badFn).to.throw();
               *
               * When one argument is provided, and it's an error constructor, `.throw`
               * invokes the target function and asserts that an error is thrown that's an
               * instance of that error constructor.
               *
               *     var badFn = function () { throw new TypeError('Illegal salmon!'); };
               *
               *     expect(badFn).to.throw(TypeError);
               *
               * When one argument is provided, and it's an error instance, `.throw` invokes
               * the target function and asserts that an error is thrown that's strictly
               * (`===`) equal to that error instance.
               *
               *     var err = new TypeError('Illegal salmon!');
               *     var badFn = function () { throw err; };
               *
               *     expect(badFn).to.throw(err);
               *
               * When one argument is provided, and it's a string, `.throw` invokes the
               * target function and asserts that an error is thrown with a message that
               * contains that string.
               *
               *     var badFn = function () { throw new TypeError('Illegal salmon!'); };
               *
               *     expect(badFn).to.throw('salmon');
               *
               * When one argument is provided, and it's a regular expression, `.throw`
               * invokes the target function and asserts that an error is thrown with a
               * message that matches that regular expression.
               *
               *     var badFn = function () { throw new TypeError('Illegal salmon!'); };
               *
               *     expect(badFn).to.throw(/salmon/);
               *
               * When two arguments are provided, and the first is an error instance or
               * constructor, and the second is a string or regular expression, `.throw`
               * invokes the function and asserts that an error is thrown that fulfills both
               * conditions as described above.
               *
               *     var err = new TypeError('Illegal salmon!');
               *     var badFn = function () { throw err; };
               *
               *     expect(badFn).to.throw(TypeError, 'salmon');
               *     expect(badFn).to.throw(TypeError, /salmon/);
               *     expect(badFn).to.throw(err, 'salmon');
               *     expect(badFn).to.throw(err, /salmon/);
               *
               * Add `.not` earlier in the chain to negate `.throw`.
               *
               *     var goodFn = function () {};
               *
               *     expect(goodFn).to.not.throw();
               *
               * However, it's dangerous to negate `.throw` when providing any arguments.
               * The problem is that it creates uncertain expectations by asserting that the
               * target either doesn't throw an error, or that it throws an error but of a
               * different type than the given type, or that it throws an error of the given
               * type but with a message that doesn't include the given string. It's often
               * best to identify the exact output that's expected, and then write an
               * assertion that only accepts that exact output.
               *
               * When the target isn't expected to throw an error, it's often best to assert
               * exactly that.
               *
               *     var goodFn = function () {};
               *
               *     expect(goodFn).to.not.throw(); // Recommended
               *     expect(goodFn).to.not.throw(ReferenceError, 'x'); // Not recommended
               *
               * When the target is expected to throw an error, it's often best to assert
               * that the error is of its expected type, and has a message that includes an
               * expected string, rather than asserting that it doesn't have one of many
               * unexpected types, and doesn't have a message that includes some string.
               *
               *     var badFn = function () { throw new TypeError('Illegal salmon!'); };
               *
               *     expect(badFn).to.throw(TypeError, 'salmon'); // Recommended
               *     expect(badFn).to.not.throw(ReferenceError, 'x'); // Not recommended
               *
               * `.throw` changes the target of any assertions that follow in the chain to
               * be the error object that's thrown.
               *
               *     var err = new TypeError('Illegal salmon!');
               *     err.code = 42;
               *     var badFn = function () { throw err; };
               *
               *     expect(badFn).to.throw(TypeError).with.property('code', 42);
               *
               * `.throw` accepts an optional `msg` argument which is a custom error message
               * to show when the assertion fails. The message can also be given as the
               * second argument to `expect`. When not providing two arguments, always use
               * the second form.
               *
               *     var goodFn = function () {};
               *
               *     expect(goodFn).to.throw(TypeError, 'x', 'nooo why fail??');
               *     expect(goodFn, 'nooo why fail??').to.throw();
               *
               * Due to limitations in ES5, `.throw` may not always work as expected when
               * using a transpiler such as Babel or TypeScript. In particular, it may
               * produce unexpected results when subclassing the built-in `Error` object and
               * then passing the subclassed constructor to `.throw`. See your transpiler's
               * docs for details:
               *
               * - ([Babel](https://babeljs.io/docs/usage/caveats/#classes))
               * - ([TypeScript](https://github.com/Microsoft/TypeScript/wiki/Breaking-Changes#extending-built-ins-like-error-array-and-map-may-no-longer-work))
               *
               * Beware of some common mistakes when using the `throw` assertion. One common
               * mistake is to accidentally invoke the function yourself instead of letting
               * the `throw` assertion invoke the function for you. For example, when
               * testing if a function named `fn` throws, provide `fn` instead of `fn()` as
               * the target for the assertion.
               *
               *     expect(fn).to.throw();     // Good! Tests `fn` as desired
               *     expect(fn()).to.throw();   // Bad! Tests result of `fn()`, not `fn`
               *
               * If you need to assert that your function `fn` throws when passed certain
               * arguments, then wrap a call to `fn` inside of another function.
               *
               *     expect(function () { fn(42); }).to.throw();  // Function expression
               *     expect(() => fn(42)).to.throw();             // ES6 arrow function
               *
               * Another common mistake is to provide an object method (or any stand-alone
               * function that relies on `this`) as the target of the assertion. Doing so is
               * problematic because the `this` context will be lost when the function is
               * invoked by `.throw`; there's no way for it to know what `this` is supposed
               * to be. There are two ways around this problem. One solution is to wrap the
               * method or function call inside of another function. Another solution is to
               * use `bind`.
               *
               *     expect(function () { cat.meow(); }).to.throw();  // Function expression
               *     expect(() => cat.meow()).to.throw();             // ES6 arrow function
               *     expect(cat.meow.bind(cat)).to.throw();           // Bind
               *
               * Finally, it's worth mentioning that it's a best practice in JavaScript to
               * only throw `Error` and derivatives of `Error` such as `ReferenceError`,
               * `TypeError`, and user-defined objects that extend `Error`. No other type of
               * value will generate a stack trace when initialized. With that said, the
               * `throw` assertion does technically support any type of value being thrown,
               * not just `Error` and its derivatives.
               *
               * The aliases `.throws` and `.Throw` can be used interchangeably with
               * `.throw`.
               *
               * @name throw
               * @alias throws
               * @alias Throw
               * @param {Error|ErrorConstructor} errorLike
               * @param {String|RegExp} errMsgMatcher error message
               * @param {String} msg _optional_
               * @see https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Error#Error_types
               * @returns error for chaining (null if no error)
               * @namespace BDD
               * @api public
               */
  
              function assertThrows(errorLike, errMsgMatcher, msg) {
                if (msg) flag(this, 'message', msg);
                var obj = flag(this, 'object'),
                  ssfi = flag(this, 'ssfi'),
                  flagMsg = flag(this, 'message'),
                  negate = flag(this, 'negate') || false;
                new Assertion(obj, flagMsg, ssfi, true).is.a('function');
  
                if (errorLike instanceof RegExp || typeof errorLike === 'string') {
                  errMsgMatcher = errorLike;
                  errorLike = null;
                }
  
                var caughtErr;
                try {
                  obj();
                } catch (err) {
                  caughtErr = err;
                }
  
                // If we have the negate flag enabled and at least one valid argument it means we do expect an error
                // but we want it to match a given set of criteria
                var everyArgIsUndefined = errorLike === undefined && errMsgMatcher === undefined;
  
                // If we've got the negate flag enabled and both args, we should only fail if both aren't compatible
                // See Issue #551 and PR #683@GitHub
                var everyArgIsDefined = Boolean(errorLike && errMsgMatcher);
                var errorLikeFail = false;
                var errMsgMatcherFail = false;
  
                // Checking if error was thrown
                if (everyArgIsUndefined || (!everyArgIsUndefined && !negate)) {
                  // We need this to display results correctly according to their types
                  var errorLikeString = 'an error';
                  if (errorLike instanceof Error) {
                    errorLikeString = '#{exp}';
                  } else if (errorLike) {
                    errorLikeString = _.checkError.getConstructorName(errorLike);
                  }
  
                  this.assert(
                    caughtErr,
                    'expected #{this} to throw ' + errorLikeString,
                    'expected #{this} to not throw an error but #{act} was thrown',
                    errorLike && errorLike.toString(),
                    caughtErr instanceof Error
                      ? caughtErr.toString()
                      : typeof caughtErr === 'string'
                      ? caughtErr
                      : caughtErr && _.checkError.getConstructorName(caughtErr)
                  );
                }
  
                if (errorLike && caughtErr) {
                  // We should compare instances only if `errorLike` is an instance of `Error`
                  if (errorLike instanceof Error) {
                    var isCompatibleInstance = _.checkError.compatibleInstance(caughtErr, errorLike);
  
                    if (isCompatibleInstance === negate) {
                      // These checks were created to ensure we won't fail too soon when we've got both args and a negate
                      // See Issue #551 and PR #683@GitHub
                      if (everyArgIsDefined && negate) {
                        errorLikeFail = true;
                      } else {
                        this.assert(
                          negate,
                          'expected #{this} to throw #{exp} but #{act} was thrown',
                          'expected #{this} to not throw #{exp}' +
                            (caughtErr && !negate ? ' but #{act} was thrown' : ''),
                          errorLike.toString(),
                          caughtErr.toString()
                        );
                      }
                    }
                  }
  
                  var isCompatibleConstructor = _.checkError.compatibleConstructor(
                    caughtErr,
                    errorLike
                  );
                  if (isCompatibleConstructor === negate) {
                    if (everyArgIsDefined && negate) {
                      errorLikeFail = true;
                    } else {
                      this.assert(
                        negate,
                        'expected #{this} to throw #{exp} but #{act} was thrown',
                        'expected #{this} to not throw #{exp}' +
                          (caughtErr ? ' but #{act} was thrown' : ''),
                        errorLike instanceof Error
                          ? errorLike.toString()
                          : errorLike && _.checkError.getConstructorName(errorLike),
                        caughtErr instanceof Error
                          ? caughtErr.toString()
                          : caughtErr && _.checkError.getConstructorName(caughtErr)
                      );
                    }
                  }
                }
  
                if (caughtErr && errMsgMatcher !== undefined && errMsgMatcher !== null) {
                  // Here we check compatible messages
                  var placeholder = 'including';
                  if (errMsgMatcher instanceof RegExp) {
                    placeholder = 'matching';
                  }
  
                  var isCompatibleMessage = _.checkError.compatibleMessage(caughtErr, errMsgMatcher);
                  if (isCompatibleMessage === negate) {
                    if (everyArgIsDefined && negate) {
                      errMsgMatcherFail = true;
                    } else {
                      this.assert(
                        negate,
                        'expected #{this} to throw error ' + placeholder + ' #{exp} but got #{act}',
                        'expected #{this} to throw error not ' + placeholder + ' #{exp}',
                        errMsgMatcher,
                        _.checkError.getMessage(caughtErr)
                      );
                    }
                  }
                }
  
                // If both assertions failed and both should've matched we throw an error
                if (errorLikeFail && errMsgMatcherFail) {
                  this.assert(
                    negate,
                    'expected #{this} to throw #{exp} but #{act} was thrown',
                    'expected #{this} to not throw #{exp}' +
                      (caughtErr ? ' but #{act} was thrown' : ''),
                    errorLike instanceof Error
                      ? errorLike.toString()
                      : errorLike && _.checkError.getConstructorName(errorLike),
                    caughtErr instanceof Error
                      ? caughtErr.toString()
                      : caughtErr && _.checkError.getConstructorName(caughtErr)
                  );
                }
  
                flag(this, 'object', caughtErr);
              }
  
              Assertion.addMethod('throw', assertThrows);
              Assertion.addMethod('throws', assertThrows);
              Assertion.addMethod('Throw', assertThrows);
  
              /**
               * ### .respondTo(method[, msg])
               *
               * When the target is a non-function object, `.respondTo` asserts that the
               * target has a method with the given name `method`. The method can be own or
               * inherited, and it can be enumerable or non-enumerable.
               *
               *     function Cat () {}
               *     Cat.prototype.meow = function () {};
               *
               *     expect(new Cat()).to.respondTo('meow');
               *
               * When the target is a function, `.respondTo` asserts that the target's
               * `prototype` property has a method with the given name `method`. Again, the
               * method can be own or inherited, and it can be enumerable or non-enumerable.
               *
               *     function Cat () {}
               *     Cat.prototype.meow = function () {};
               *
               *     expect(Cat).to.respondTo('meow');
               *
               * Add `.itself` earlier in the chain to force `.respondTo` to treat the
               * target as a non-function object, even if it's a function. Thus, it asserts
               * that the target has a method with the given name `method`, rather than
               * asserting that the target's `prototype` property has a method with the
               * given name `method`.
               *
               *     function Cat () {}
               *     Cat.prototype.meow = function () {};
               *     Cat.hiss = function () {};
               *
               *     expect(Cat).itself.to.respondTo('hiss').but.not.respondTo('meow');
               *
               * When not adding `.itself`, it's important to check the target's type before
               * using `.respondTo`. See the `.a` doc for info on checking a target's type.
               *
               *     function Cat () {}
               *     Cat.prototype.meow = function () {};
               *
               *     expect(new Cat()).to.be.an('object').that.respondsTo('meow');
               *
               * Add `.not` earlier in the chain to negate `.respondTo`.
               *
               *     function Dog () {}
               *     Dog.prototype.bark = function () {};
               *
               *     expect(new Dog()).to.not.respondTo('meow');
               *
               * `.respondTo` accepts an optional `msg` argument which is a custom error
               * message to show when the assertion fails. The message can also be given as
               * the second argument to `expect`.
               *
               *     expect({}).to.respondTo('meow', 'nooo why fail??');
               *     expect({}, 'nooo why fail??').to.respondTo('meow');
               *
               * The alias `.respondsTo` can be used interchangeably with `.respondTo`.
               *
               * @name respondTo
               * @alias respondsTo
               * @param {String} method
               * @param {String} msg _optional_
               * @namespace BDD
               * @api public
               */
  
              function respondTo(method, msg) {
                if (msg) flag(this, 'message', msg);
                var obj = flag(this, 'object'),
                  itself = flag(this, 'itself'),
                  context =
                    'function' === typeof obj && !itself ? obj.prototype[method] : obj[method];
  
                this.assert(
                  'function' === typeof context,
                  'expected #{this} to respond to ' + _.inspect(method),
                  'expected #{this} to not respond to ' + _.inspect(method)
                );
              }
  
              Assertion.addMethod('respondTo', respondTo);
              Assertion.addMethod('respondsTo', respondTo);
  
              /**
               * ### .itself
               *
               * Forces all `.respondTo` assertions that follow in the chain to behave as if
               * the target is a non-function object, even if it's a function. Thus, it
               * causes `.respondTo` to assert that the target has a method with the given
               * name, rather than asserting that the target's `prototype` property has a
               * method with the given name.
               *
               *     function Cat () {}
               *     Cat.prototype.meow = function () {};
               *     Cat.hiss = function () {};
               *
               *     expect(Cat).itself.to.respondTo('hiss').but.not.respondTo('meow');
               *
               * @name itself
               * @namespace BDD
               * @api public
               */
  
              Assertion.addProperty('itself', function () {
                flag(this, 'itself', true);
              });
  
              /**
               * ### .satisfy(matcher[, msg])
               *
               * Invokes the given `matcher` function with the target being passed as the
               * first argument, and asserts that the value returned is truthy.
               *
               *     expect(1).to.satisfy(function(num) {
               *       return num > 0;
               *     });
               *
               * Add `.not` earlier in the chain to negate `.satisfy`.
               *
               *     expect(1).to.not.satisfy(function(num) {
               *       return num > 2;
               *     });
               *
               * `.satisfy` accepts an optional `msg` argument which is a custom error
               * message to show when the assertion fails. The message can also be given as
               * the second argument to `expect`.
               *
               *     expect(1).to.satisfy(function(num) {
               *       return num > 2;
               *     }, 'nooo why fail??');
               *
               *     expect(1, 'nooo why fail??').to.satisfy(function(num) {
               *       return num > 2;
               *     });
               *
               * The alias `.satisfies` can be used interchangeably with `.satisfy`.
               *
               * @name satisfy
               * @alias satisfies
               * @param {Function} matcher
               * @param {String} msg _optional_
               * @namespace BDD
               * @api public
               */
  
              function satisfy(matcher, msg) {
                if (msg) flag(this, 'message', msg);
                var obj = flag(this, 'object');
                var result = matcher(obj);
                this.assert(
                  result,
                  'expected #{this} to satisfy ' + _.objDisplay(matcher),
                  'expected #{this} to not satisfy' + _.objDisplay(matcher),
                  flag(this, 'negate') ? false : true,
                  result
                );
              }
  
              Assertion.addMethod('satisfy', satisfy);
              Assertion.addMethod('satisfies', satisfy);
  
              /**
               * ### .closeTo(expected, delta[, msg])
               *
               * Asserts that the target is a number that's within a given +/- `delta` range
               * of the given number `expected`. However, it's often best to assert that the
               * target is equal to its expected value.
               *
               *     // Recommended
               *     expect(1.5).to.equal(1.5);
               *
               *     // Not recommended
               *     expect(1.5).to.be.closeTo(1, 0.5);
               *     expect(1.5).to.be.closeTo(2, 0.5);
               *     expect(1.5).to.be.closeTo(1, 1);
               *
               * Add `.not` earlier in the chain to negate `.closeTo`.
               *
               *     expect(1.5).to.equal(1.5); // Recommended
               *     expect(1.5).to.not.be.closeTo(3, 1); // Not recommended
               *
               * `.closeTo` accepts an optional `msg` argument which is a custom error
               * message to show when the assertion fails. The message can also be given as
               * the second argument to `expect`.
               *
               *     expect(1.5).to.be.closeTo(3, 1, 'nooo why fail??');
               *     expect(1.5, 'nooo why fail??').to.be.closeTo(3, 1);
               *
               * The alias `.approximately` can be used interchangeably with `.closeTo`.
               *
               * @name closeTo
               * @alias approximately
               * @param {Number} expected
               * @param {Number} delta
               * @param {String} msg _optional_
               * @namespace BDD
               * @api public
               */
  
              function closeTo(expected, delta, msg) {
                if (msg) flag(this, 'message', msg);
                var obj = flag(this, 'object'),
                  flagMsg = flag(this, 'message'),
                  ssfi = flag(this, 'ssfi');
  
                new Assertion(obj, flagMsg, ssfi, true).is.a('number');
                if (typeof expected !== 'number' || typeof delta !== 'number') {
                  flagMsg = flagMsg ? flagMsg + ': ' : '';
                  throw new AssertionError(
                    flagMsg + 'the arguments to closeTo or approximately must be numbers',
                    undefined,
                    ssfi
                  );
                }
  
                this.assert(
                  Math.abs(obj - expected) <= delta,
                  'expected #{this} to be close to ' + expected + ' +/- ' + delta,
                  'expected #{this} not to be close to ' + expected + ' +/- ' + delta
                );
              }
  
              Assertion.addMethod('closeTo', closeTo);
              Assertion.addMethod('approximately', closeTo);
  
              // Note: Duplicates are ignored if testing for inclusion instead of sameness.
              function isSubsetOf(subset, superset, cmp, contains, ordered) {
                if (!contains) {
                  if (subset.length !== superset.length) return false;
                  superset = superset.slice();
                }
  
                return subset.every(function (elem, idx) {
                  if (ordered) return cmp ? cmp(elem, superset[idx]) : elem === superset[idx];
  
                  if (!cmp) {
                    var matchIdx = superset.indexOf(elem);
                    if (matchIdx === -1) return false;
  
                    // Remove match from superset so not counted twice if duplicate in subset.
                    if (!contains) superset.splice(matchIdx, 1);
                    return true;
                  }
  
                  return superset.some(function (elem2, matchIdx) {
                    if (!cmp(elem, elem2)) return false;
  
                    // Remove match from superset so not counted twice if duplicate in subset.
                    if (!contains) superset.splice(matchIdx, 1);
                    return true;
                  });
                });
              }
  
              /**
               * ### .members(set[, msg])
               *
               * Asserts that the target array has the same members as the given array
               * `set`.
               *
               *     expect([1, 2, 3]).to.have.members([2, 1, 3]);
               *     expect([1, 2, 2]).to.have.members([2, 1, 2]);
               *
               * By default, members are compared using strict (`===`) equality. Add `.deep`
               * earlier in the chain to use deep equality instead. See the `deep-eql`
               * project page for info on the deep equality algorithm:
               * https://github.com/chaijs/deep-eql.
               *
               *     // Target array deeply (but not strictly) has member `{a: 1}`
               *     expect([{a: 1}]).to.have.deep.members([{a: 1}]);
               *     expect([{a: 1}]).to.not.have.members([{a: 1}]);
               *
               * By default, order doesn't matter. Add `.ordered` earlier in the chain to
               * require that members appear in the same order.
               *
               *     expect([1, 2, 3]).to.have.ordered.members([1, 2, 3]);
               *     expect([1, 2, 3]).to.have.members([2, 1, 3])
               *       .but.not.ordered.members([2, 1, 3]);
               *
               * By default, both arrays must be the same size. Add `.include` earlier in
               * the chain to require that the target's members be a superset of the
               * expected members. Note that duplicates are ignored in the subset when
               * `.include` is added.
               *
               *     // Target array is a superset of [1, 2] but not identical
               *     expect([1, 2, 3]).to.include.members([1, 2]);
               *     expect([1, 2, 3]).to.not.have.members([1, 2]);
               *
               *     // Duplicates in the subset are ignored
               *     expect([1, 2, 3]).to.include.members([1, 2, 2, 2]);
               *
               * `.deep`, `.ordered`, and `.include` can all be combined. However, if
               * `.include` and `.ordered` are combined, the ordering begins at the start of
               * both arrays.
               *
               *     expect([{a: 1}, {b: 2}, {c: 3}])
               *       .to.include.deep.ordered.members([{a: 1}, {b: 2}])
               *       .but.not.include.deep.ordered.members([{b: 2}, {c: 3}]);
               *
               * Add `.not` earlier in the chain to negate `.members`. However, it's
               * dangerous to do so. The problem is that it creates uncertain expectations
               * by asserting that the target array doesn't have all of the same members as
               * the given array `set` but may or may not have some of them. It's often best
               * to identify the exact output that's expected, and then write an assertion
               * that only accepts that exact output.
               *
               *     expect([1, 2]).to.not.include(3).and.not.include(4); // Recommended
               *     expect([1, 2]).to.not.have.members([3, 4]); // Not recommended
               *
               * `.members` accepts an optional `msg` argument which is a custom error
               * message to show when the assertion fails. The message can also be given as
               * the second argument to `expect`.
               *
               *     expect([1, 2]).to.have.members([1, 2, 3], 'nooo why fail??');
               *     expect([1, 2], 'nooo why fail??').to.have.members([1, 2, 3]);
               *
               * @name members
               * @param {Array} set
               * @param {String} msg _optional_
               * @namespace BDD
               * @api public
               */
  
              Assertion.addMethod('members', function (subset, msg) {
                if (msg) flag(this, 'message', msg);
                var obj = flag(this, 'object'),
                  flagMsg = flag(this, 'message'),
                  ssfi = flag(this, 'ssfi');
  
                new Assertion(obj, flagMsg, ssfi, true).to.be.an('array');
                new Assertion(subset, flagMsg, ssfi, true).to.be.an('array');
  
                var contains = flag(this, 'contains');
                var ordered = flag(this, 'ordered');
  
                var subject, failMsg, failNegateMsg;
  
                if (contains) {
                  subject = ordered ? 'an ordered superset' : 'a superset';
                  failMsg = 'expected #{this} to be ' + subject + ' of #{exp}';
                  failNegateMsg = 'expected #{this} to not be ' + subject + ' of #{exp}';
                } else {
                  subject = ordered ? 'ordered members' : 'members';
                  failMsg = 'expected #{this} to have the same ' + subject + ' as #{exp}';
                  failNegateMsg = 'expected #{this} to not have the same ' + subject + ' as #{exp}';
                }
  
                var cmp = flag(this, 'deep') ? _.eql : undefined;
  
                this.assert(
                  isSubsetOf(subset, obj, cmp, contains, ordered),
                  failMsg,
                  failNegateMsg,
                  subset,
                  obj,
                  true
                );
              });
  
              /**
               * ### .oneOf(list[, msg])
               *
               * Asserts that the target is a member of the given array `list`. However,
               * it's often best to assert that the target is equal to its expected value.
               *
               *     expect(1).to.equal(1); // Recommended
               *     expect(1).to.be.oneOf([1, 2, 3]); // Not recommended
               *
               * Comparisons are performed using strict (`===`) equality.
               *
               * Add `.not` earlier in the chain to negate `.oneOf`.
               *
               *     expect(1).to.equal(1); // Recommended
               *     expect(1).to.not.be.oneOf([2, 3, 4]); // Not recommended
               *
               * `.oneOf` accepts an optional `msg` argument which is a custom error message
               * to show when the assertion fails. The message can also be given as the
               * second argument to `expect`.
               *
               *     expect(1).to.be.oneOf([2, 3, 4], 'nooo why fail??');
               *     expect(1, 'nooo why fail??').to.be.oneOf([2, 3, 4]);
               *
               * @name oneOf
               * @param {Array<*>} list
               * @param {String} msg _optional_
               * @namespace BDD
               * @api public
               */
  
              function oneOf(list, msg) {
                if (msg) flag(this, 'message', msg);
                var expected = flag(this, 'object'),
                  flagMsg = flag(this, 'message'),
                  ssfi = flag(this, 'ssfi');
                new Assertion(list, flagMsg, ssfi, true).to.be.an('array');
  
                this.assert(
                  list.indexOf(expected) > -1,
                  'expected #{this} to be one of #{exp}',
                  'expected #{this} to not be one of #{exp}',
                  list,
                  expected
                );
              }
  
              Assertion.addMethod('oneOf', oneOf);
  
              /**
               * ### .change(subject[, prop[, msg]])
               *
               * When one argument is provided, `.change` asserts that the given function
               * `subject` returns a different value when it's invoked before the target
               * function compared to when it's invoked afterward. However, it's often best
               * to assert that `subject` is equal to its expected value.
               *
               *     var dots = ''
               *       , addDot = function () { dots += '.'; }
               *       , getDots = function () { return dots; };
               *
               *     // Recommended
               *     expect(getDots()).to.equal('');
               *     addDot();
               *     expect(getDots()).to.equal('.');
               *
               *     // Not recommended
               *     expect(addDot).to.change(getDots);
               *
               * When two arguments are provided, `.change` asserts that the value of the
               * given object `subject`'s `prop` property is different before invoking the
               * target function compared to afterward.
               *
               *     var myObj = {dots: ''}
               *       , addDot = function () { myObj.dots += '.'; };
               *
               *     // Recommended
               *     expect(myObj).to.have.property('dots', '');
               *     addDot();
               *     expect(myObj).to.have.property('dots', '.');
               *
               *     // Not recommended
               *     expect(addDot).to.change(myObj, 'dots');
               *
               * Strict (`===`) equality is used to compare before and after values.
               *
               * Add `.not` earlier in the chain to negate `.change`.
               *
               *     var dots = ''
               *       , noop = function () {}
               *       , getDots = function () { return dots; };
               *
               *     expect(noop).to.not.change(getDots);
               *
               *     var myObj = {dots: ''}
               *       , noop = function () {};
               *
               *     expect(noop).to.not.change(myObj, 'dots');
               *
               * `.change` accepts an optional `msg` argument which is a custom error
               * message to show when the assertion fails. The message can also be given as
               * the second argument to `expect`. When not providing two arguments, always
               * use the second form.
               *
               *     var myObj = {dots: ''}
               *       , addDot = function () { myObj.dots += '.'; };
               *
               *     expect(addDot).to.not.change(myObj, 'dots', 'nooo why fail??');
               *
               *     var dots = ''
               *       , addDot = function () { dots += '.'; }
               *       , getDots = function () { return dots; };
               *
               *     expect(addDot, 'nooo why fail??').to.not.change(getDots);
               *
               * `.change` also causes all `.by` assertions that follow in the chain to
               * assert how much a numeric subject was increased or decreased by. However,
               * it's dangerous to use `.change.by`. The problem is that it creates
               * uncertain expectations by asserting that the subject either increases by
               * the given delta, or that it decreases by the given delta. It's often best
               * to identify the exact output that's expected, and then write an assertion
               * that only accepts that exact output.
               *
               *     var myObj = {val: 1}
               *       , addTwo = function () { myObj.val += 2; }
               *       , subtractTwo = function () { myObj.val -= 2; };
               *
               *     expect(addTwo).to.increase(myObj, 'val').by(2); // Recommended
               *     expect(addTwo).to.change(myObj, 'val').by(2); // Not recommended
               *
               *     expect(subtractTwo).to.decrease(myObj, 'val').by(2); // Recommended
               *     expect(subtractTwo).to.change(myObj, 'val').by(2); // Not recommended
               *
               * The alias `.changes` can be used interchangeably with `.change`.
               *
               * @name change
               * @alias changes
               * @param {String} subject
               * @param {String} prop name _optional_
               * @param {String} msg _optional_
               * @namespace BDD
               * @api public
               */
  
              function assertChanges(subject, prop, msg) {
                if (msg) flag(this, 'message', msg);
                var fn = flag(this, 'object'),
                  flagMsg = flag(this, 'message'),
                  ssfi = flag(this, 'ssfi');
                new Assertion(fn, flagMsg, ssfi, true).is.a('function');
  
                var initial;
                if (!prop) {
                  new Assertion(subject, flagMsg, ssfi, true).is.a('function');
                  initial = subject();
                } else {
                  new Assertion(subject, flagMsg, ssfi, true).to.have.property(prop);
                  initial = subject[prop];
                }
  
                fn();
  
                var final = prop === undefined || prop === null ? subject() : subject[prop];
                var msgObj = prop === undefined || prop === null ? initial : '.' + prop;
  
                // This gets flagged because of the .by(delta) assertion
                flag(this, 'deltaMsgObj', msgObj);
                flag(this, 'initialDeltaValue', initial);
                flag(this, 'finalDeltaValue', final);
                flag(this, 'deltaBehavior', 'change');
                flag(this, 'realDelta', final !== initial);
  
                this.assert(
                  initial !== final,
                  'expected ' + msgObj + ' to change',
                  'expected ' + msgObj + ' to not change'
                );
              }
  
              Assertion.addMethod('change', assertChanges);
              Assertion.addMethod('changes', assertChanges);
  
              /**
               * ### .increase(subject[, prop[, msg]])
               *
               * When one argument is provided, `.increase` asserts that the given function
               * `subject` returns a greater number when it's invoked after invoking the
               * target function compared to when it's invoked beforehand. `.increase` also
               * causes all `.by` assertions that follow in the chain to assert how much
               * greater of a number is returned. It's often best to assert that the return
               * value increased by the expected amount, rather than asserting it increased
               * by any amount.
               *
               *     var val = 1
               *       , addTwo = function () { val += 2; }
               *       , getVal = function () { return val; };
               *
               *     expect(addTwo).to.increase(getVal).by(2); // Recommended
               *     expect(addTwo).to.increase(getVal); // Not recommended
               *
               * When two arguments are provided, `.increase` asserts that the value of the
               * given object `subject`'s `prop` property is greater after invoking the
               * target function compared to beforehand.
               *
               *     var myObj = {val: 1}
               *       , addTwo = function () { myObj.val += 2; };
               *
               *     expect(addTwo).to.increase(myObj, 'val').by(2); // Recommended
               *     expect(addTwo).to.increase(myObj, 'val'); // Not recommended
               *
               * Add `.not` earlier in the chain to negate `.increase`. However, it's
               * dangerous to do so. The problem is that it creates uncertain expectations
               * by asserting that the subject either decreases, or that it stays the same.
               * It's often best to identify the exact output that's expected, and then
               * write an assertion that only accepts that exact output.
               *
               * When the subject is expected to decrease, it's often best to assert that it
               * decreased by the expected amount.
               *
               *     var myObj = {val: 1}
               *       , subtractTwo = function () { myObj.val -= 2; };
               *
               *     expect(subtractTwo).to.decrease(myObj, 'val').by(2); // Recommended
               *     expect(subtractTwo).to.not.increase(myObj, 'val'); // Not recommended
               *
               * When the subject is expected to stay the same, it's often best to assert
               * exactly that.
               *
               *     var myObj = {val: 1}
               *       , noop = function () {};
               *
               *     expect(noop).to.not.change(myObj, 'val'); // Recommended
               *     expect(noop).to.not.increase(myObj, 'val'); // Not recommended
               *
               * `.increase` accepts an optional `msg` argument which is a custom error
               * message to show when the assertion fails. The message can also be given as
               * the second argument to `expect`. When not providing two arguments, always
               * use the second form.
               *
               *     var myObj = {val: 1}
               *       , noop = function () {};
               *
               *     expect(noop).to.increase(myObj, 'val', 'nooo why fail??');
               *
               *     var val = 1
               *       , noop = function () {}
               *       , getVal = function () { return val; };
               *
               *     expect(noop, 'nooo why fail??').to.increase(getVal);
               *
               * The alias `.increases` can be used interchangeably with `.increase`.
               *
               * @name increase
               * @alias increases
               * @param {String|Function} subject
               * @param {String} prop name _optional_
               * @param {String} msg _optional_
               * @namespace BDD
               * @api public
               */
  
              function assertIncreases(subject, prop, msg) {
                if (msg) flag(this, 'message', msg);
                var fn = flag(this, 'object'),
                  flagMsg = flag(this, 'message'),
                  ssfi = flag(this, 'ssfi');
                new Assertion(fn, flagMsg, ssfi, true).is.a('function');
  
                var initial;
                if (!prop) {
                  new Assertion(subject, flagMsg, ssfi, true).is.a('function');
                  initial = subject();
                } else {
                  new Assertion(subject, flagMsg, ssfi, true).to.have.property(prop);
                  initial = subject[prop];
                }
  
                // Make sure that the target is a number
                new Assertion(initial, flagMsg, ssfi, true).is.a('number');
  
                fn();
  
                var final = prop === undefined || prop === null ? subject() : subject[prop];
                var msgObj = prop === undefined || prop === null ? initial : '.' + prop;
  
                flag(this, 'deltaMsgObj', msgObj);
                flag(this, 'initialDeltaValue', initial);
                flag(this, 'finalDeltaValue', final);
                flag(this, 'deltaBehavior', 'increase');
                flag(this, 'realDelta', final - initial);
  
                this.assert(
                  final - initial > 0,
                  'expected ' + msgObj + ' to increase',
                  'expected ' + msgObj + ' to not increase'
                );
              }
  
              Assertion.addMethod('increase', assertIncreases);
              Assertion.addMethod('increases', assertIncreases);
  
              /**
               * ### .decrease(subject[, prop[, msg]])
               *
               * When one argument is provided, `.decrease` asserts that the given function
               * `subject` returns a lesser number when it's invoked after invoking the
               * target function compared to when it's invoked beforehand. `.decrease` also
               * causes all `.by` assertions that follow in the chain to assert how much
               * lesser of a number is returned. It's often best to assert that the return
               * value decreased by the expected amount, rather than asserting it decreased
               * by any amount.
               *
               *     var val = 1
               *       , subtractTwo = function () { val -= 2; }
               *       , getVal = function () { return val; };
               *
               *     expect(subtractTwo).to.decrease(getVal).by(2); // Recommended
               *     expect(subtractTwo).to.decrease(getVal); // Not recommended
               *
               * When two arguments are provided, `.decrease` asserts that the value of the
               * given object `subject`'s `prop` property is lesser after invoking the
               * target function compared to beforehand.
               *
               *     var myObj = {val: 1}
               *       , subtractTwo = function () { myObj.val -= 2; };
               *
               *     expect(subtractTwo).to.decrease(myObj, 'val').by(2); // Recommended
               *     expect(subtractTwo).to.decrease(myObj, 'val'); // Not recommended
               *
               * Add `.not` earlier in the chain to negate `.decrease`. However, it's
               * dangerous to do so. The problem is that it creates uncertain expectations
               * by asserting that the subject either increases, or that it stays the same.
               * It's often best to identify the exact output that's expected, and then
               * write an assertion that only accepts that exact output.
               *
               * When the subject is expected to increase, it's often best to assert that it
               * increased by the expected amount.
               *
               *     var myObj = {val: 1}
               *       , addTwo = function () { myObj.val += 2; };
               *
               *     expect(addTwo).to.increase(myObj, 'val').by(2); // Recommended
               *     expect(addTwo).to.not.decrease(myObj, 'val'); // Not recommended
               *
               * When the subject is expected to stay the same, it's often best to assert
               * exactly that.
               *
               *     var myObj = {val: 1}
               *       , noop = function () {};
               *
               *     expect(noop).to.not.change(myObj, 'val'); // Recommended
               *     expect(noop).to.not.decrease(myObj, 'val'); // Not recommended
               *
               * `.decrease` accepts an optional `msg` argument which is a custom error
               * message to show when the assertion fails. The message can also be given as
               * the second argument to `expect`. When not providing two arguments, always
               * use the second form.
               *
               *     var myObj = {val: 1}
               *       , noop = function () {};
               *
               *     expect(noop).to.decrease(myObj, 'val', 'nooo why fail??');
               *
               *     var val = 1
               *       , noop = function () {}
               *       , getVal = function () { return val; };
               *
               *     expect(noop, 'nooo why fail??').to.decrease(getVal);
               *
               * The alias `.decreases` can be used interchangeably with `.decrease`.
               *
               * @name decrease
               * @alias decreases
               * @param {String|Function} subject
               * @param {String} prop name _optional_
               * @param {String} msg _optional_
               * @namespace BDD
               * @api public
               */
  
              function assertDecreases(subject, prop, msg) {
                if (msg) flag(this, 'message', msg);
                var fn = flag(this, 'object'),
                  flagMsg = flag(this, 'message'),
                  ssfi = flag(this, 'ssfi');
                new Assertion(fn, flagMsg, ssfi, true).is.a('function');
  
                var initial;
                if (!prop) {
                  new Assertion(subject, flagMsg, ssfi, true).is.a('function');
                  initial = subject();
                } else {
                  new Assertion(subject, flagMsg, ssfi, true).to.have.property(prop);
                  initial = subject[prop];
                }
  
                // Make sure that the target is a number
                new Assertion(initial, flagMsg, ssfi, true).is.a('number');
  
                fn();
  
                var final = prop === undefined || prop === null ? subject() : subject[prop];
                var msgObj = prop === undefined || prop === null ? initial : '.' + prop;
  
                flag(this, 'deltaMsgObj', msgObj);
                flag(this, 'initialDeltaValue', initial);
                flag(this, 'finalDeltaValue', final);
                flag(this, 'deltaBehavior', 'decrease');
                flag(this, 'realDelta', initial - final);
  
                this.assert(
                  final - initial < 0,
                  'expected ' + msgObj + ' to decrease',
                  'expected ' + msgObj + ' to not decrease'
                );
              }
  
              Assertion.addMethod('decrease', assertDecreases);
              Assertion.addMethod('decreases', assertDecreases);
  
              /**
               * ### .by(delta[, msg])
               *
               * When following an `.increase` assertion in the chain, `.by` asserts that
               * the subject of the `.increase` assertion increased by the given `delta`.
               *
               *     var myObj = {val: 1}
               *       , addTwo = function () { myObj.val += 2; };
               *
               *     expect(addTwo).to.increase(myObj, 'val').by(2);
               *
               * When following a `.decrease` assertion in the chain, `.by` asserts that the
               * subject of the `.decrease` assertion decreased by the given `delta`.
               *
               *     var myObj = {val: 1}
               *       , subtractTwo = function () { myObj.val -= 2; };
               *
               *     expect(subtractTwo).to.decrease(myObj, 'val').by(2);
               *
               * When following a `.change` assertion in the chain, `.by` asserts that the
               * subject of the `.change` assertion either increased or decreased by the
               * given `delta`. However, it's dangerous to use `.change.by`. The problem is
               * that it creates uncertain expectations. It's often best to identify the
               * exact output that's expected, and then write an assertion that only accepts
               * that exact output.
               *
               *     var myObj = {val: 1}
               *       , addTwo = function () { myObj.val += 2; }
               *       , subtractTwo = function () { myObj.val -= 2; };
               *
               *     expect(addTwo).to.increase(myObj, 'val').by(2); // Recommended
               *     expect(addTwo).to.change(myObj, 'val').by(2); // Not recommended
               *
               *     expect(subtractTwo).to.decrease(myObj, 'val').by(2); // Recommended
               *     expect(subtractTwo).to.change(myObj, 'val').by(2); // Not recommended
               *
               * Add `.not` earlier in the chain to negate `.by`. However, it's often best
               * to assert that the subject changed by its expected delta, rather than
               * asserting that it didn't change by one of countless unexpected deltas.
               *
               *     var myObj = {val: 1}
               *       , addTwo = function () { myObj.val += 2; };
               *
               *     // Recommended
               *     expect(addTwo).to.increase(myObj, 'val').by(2);
               *
               *     // Not recommended
               *     expect(addTwo).to.increase(myObj, 'val').but.not.by(3);
               *
               * `.by` accepts an optional `msg` argument which is a custom error message to
               * show when the assertion fails. The message can also be given as the second
               * argument to `expect`.
               *
               *     var myObj = {val: 1}
               *       , addTwo = function () { myObj.val += 2; };
               *
               *     expect(addTwo).to.increase(myObj, 'val').by(3, 'nooo why fail??');
               *     expect(addTwo, 'nooo why fail??').to.increase(myObj, 'val').by(3);
               *
               * @name by
               * @param {Number} delta
               * @param {String} msg _optional_
               * @namespace BDD
               * @api public
               */
  
              function assertDelta(delta, msg) {
                if (msg) flag(this, 'message', msg);
  
                var msgObj = flag(this, 'deltaMsgObj');
                var initial = flag(this, 'initialDeltaValue');
                var final = flag(this, 'finalDeltaValue');
                var behavior = flag(this, 'deltaBehavior');
                var realDelta = flag(this, 'realDelta');
  
                var expression;
                if (behavior === 'change') {
                  expression = Math.abs(final - initial) === Math.abs(delta);
                } else {
                  expression = realDelta === Math.abs(delta);
                }
  
                this.assert(
                  expression,
                  'expected ' + msgObj + ' to ' + behavior + ' by ' + delta,
                  'expected ' + msgObj + ' to not ' + behavior + ' by ' + delta
                );
              }
  
              Assertion.addMethod('by', assertDelta);
  
              /**
               * ### .extensible
               *
               * Asserts that the target is extensible, which means that new properties can
               * be added to it. Primitives are never extensible.
               *
               *     expect({a: 1}).to.be.extensible;
               *
               * Add `.not` earlier in the chain to negate `.extensible`.
               *
               *     var nonExtensibleObject = Object.preventExtensions({})
               *       , sealedObject = Object.seal({})
               *       , frozenObject = Object.freeze({});
               *
               *     expect(nonExtensibleObject).to.not.be.extensible;
               *     expect(sealedObject).to.not.be.extensible;
               *     expect(frozenObject).to.not.be.extensible;
               *     expect(1).to.not.be.extensible;
               *
               * A custom error message can be given as the second argument to `expect`.
               *
               *     expect(1, 'nooo why fail??').to.be.extensible;
               *
               * @name extensible
               * @namespace BDD
               * @api public
               */
  
              Assertion.addProperty('extensible', function () {
                var obj = flag(this, 'object');
  
                // In ES5, if the argument to this method is a primitive, then it will cause a TypeError.
                // In ES6, a non-object argument will be treated as if it was a non-extensible ordinary object, simply return false.
                // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isExtensible
                // The following provides ES6 behavior for ES5 environments.
  
                var isExtensible = obj === Object(obj) && Object.isExtensible(obj);
  
                this.assert(
                  isExtensible,
                  'expected #{this} to be extensible',
                  'expected #{this} to not be extensible'
                );
              });
  
              /**
               * ### .sealed
               *
               * Asserts that the target is sealed, which means that new properties can't be
               * added to it, and its existing properties can't be reconfigured or deleted.
               * However, it's possible that its existing properties can still be reassigned
               * to different values. Primitives are always sealed.
               *
               *     var sealedObject = Object.seal({});
               *     var frozenObject = Object.freeze({});
               *
               *     expect(sealedObject).to.be.sealed;
               *     expect(frozenObject).to.be.sealed;
               *     expect(1).to.be.sealed;
               *
               * Add `.not` earlier in the chain to negate `.sealed`.
               *
               *     expect({a: 1}).to.not.be.sealed;
               *
               * A custom error message can be given as the second argument to `expect`.
               *
               *     expect({a: 1}, 'nooo why fail??').to.be.sealed;
               *
               * @name sealed
               * @namespace BDD
               * @api public
               */
  
              Assertion.addProperty('sealed', function () {
                var obj = flag(this, 'object');
  
                // In ES5, if the argument to this method is a primitive, then it will cause a TypeError.
                // In ES6, a non-object argument will be treated as if it was a sealed ordinary object, simply return true.
                // See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isSealed
                // The following provides ES6 behavior for ES5 environments.
  
                var isSealed = obj === Object(obj) ? Object.isSealed(obj) : true;
  
                this.assert(
                  isSealed,
                  'expected #{this} to be sealed',
                  'expected #{this} to not be sealed'
                );
              });
  
              /**
               * ### .frozen
               *
               * Asserts that the target is frozen, which means that new properties can't be
               * added to it, and its existing properties can't be reassigned to different
               * values, reconfigured, or deleted. Primitives are always frozen.
               *
               *     var frozenObject = Object.freeze({});
               *
               *     expect(frozenObject).to.be.frozen;
               *     expect(1).to.be.frozen;
               *
               * Add `.not` earlier in the chain to negate `.frozen`.
               *
               *     expect({a: 1}).to.not.be.frozen;
               *
               * A custom error message can be given as the second argument to `expect`.
               *
               *     expect({a: 1}, 'nooo why fail??').to.be.frozen;
               *
               * @name frozen
               * @namespace BDD
               * @api public
               */
  
              Assertion.addProperty('frozen', function () {
                var obj = flag(this, 'object');
  
                // In ES5, if the argument to this method is a primitive, then it will cause a TypeError.
                // In ES6, a non-object argument will be treated as if it was a frozen ordinary object, simply return true.
                // See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isFrozen
                // The following provides ES6 behavior for ES5 environments.
  
                var isFrozen = obj === Object(obj) ? Object.isFrozen(obj) : true;
  
                this.assert(
                  isFrozen,
                  'expected #{this} to be frozen',
                  'expected #{this} to not be frozen'
                );
              });
  
              /**
               * ### .finite
               *
               * Asserts that the target is a number, and isn't `NaN` or positive/negative
               * `Infinity`.
               *
               *     expect(1).to.be.finite;
               *
               * Add `.not` earlier in the chain to negate `.finite`. However, it's
               * dangerous to do so. The problem is that it creates uncertain expectations
               * by asserting that the subject either isn't a number, or that it's `NaN`, or
               * that it's positive `Infinity`, or that it's negative `Infinity`. It's often
               * best to identify the exact output that's expected, and then write an
               * assertion that only accepts that exact output.
               *
               * When the target isn't expected to be a number, it's often best to assert
               * that it's the expected type, rather than asserting that it isn't one of
               * many unexpected types.
               *
               *     expect('foo').to.be.a('string'); // Recommended
               *     expect('foo').to.not.be.finite; // Not recommended
               *
               * When the target is expected to be `NaN`, it's often best to assert exactly
               * that.
               *
               *     expect(NaN).to.be.NaN; // Recommended
               *     expect(NaN).to.not.be.finite; // Not recommended
               *
               * When the target is expected to be positive infinity, it's often best to
               * assert exactly that.
               *
               *     expect(Infinity).to.equal(Infinity); // Recommended
               *     expect(Infinity).to.not.be.finite; // Not recommended
               *
               * When the target is expected to be negative infinity, it's often best to
               * assert exactly that.
               *
               *     expect(-Infinity).to.equal(-Infinity); // Recommended
               *     expect(-Infinity).to.not.be.finite; // Not recommended
               *
               * A custom error message can be given as the second argument to `expect`.
               *
               *     expect('foo', 'nooo why fail??').to.be.finite;
               *
               * @name finite
               * @namespace BDD
               * @api public
               */
  
              Assertion.addProperty('finite', function (msg) {
                var obj = flag(this, 'object');
  
                this.assert(
                  typeof obj === 'number' && isFinite(obj),
                  'expected #{this} to be a finite number',
                  'expected #{this} to not be a finite number'
                );
              });
            };
          },
          {},
        ],
        6: [
          function (require, module, exports) {
            /*!
             * chai
             * Copyright(c) 2011-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            module.exports = function (chai, util) {
              /*!
               * Chai dependencies.
               */
  
              var Assertion = chai.Assertion,
                flag = util.flag;
  
              /*!
               * Module export.
               */
  
              /**
               * ### assert(expression, message)
               *
               * Write your own test expressions.
               *
               *     assert('foo' !== 'bar', 'foo is not bar');
               *     assert(Array.isArray([]), 'empty arrays are arrays');
               *
               * @param {Mixed} expression to test for truthiness
               * @param {String} message to display on error
               * @name assert
               * @namespace Assert
               * @api public
               */
  
              var assert = (chai.assert = function (express, errmsg) {
                var test = new Assertion(null, null, chai.assert, true);
                test.assert(express, errmsg, '[ negation message unavailable ]');
              });
  
              /**
               * ### .fail([message])
               * ### .fail(actual, expected, [message], [operator])
               *
               * Throw a failure. Node.js `assert` module-compatible.
               *
               *     assert.fail();
               *     assert.fail("custom error message");
               *     assert.fail(1, 2);
               *     assert.fail(1, 2, "custom error message");
               *     assert.fail(1, 2, "custom error message", ">");
               *     assert.fail(1, 2, undefined, ">");
               *
               * @name fail
               * @param {Mixed} actual
               * @param {Mixed} expected
               * @param {String} message
               * @param {String} operator
               * @namespace Assert
               * @api public
               */
  
              assert.fail = function (actual, expected, message, operator) {
                if (arguments.length < 2) {
                  // Comply with Node's fail([message]) interface
  
                  message = actual;
                  actual = undefined;
                }
  
                message = message || 'assert.fail()';
                throw new chai.AssertionError(
                  message,
                  {
                    actual: actual,
                    expected: expected,
                    operator: operator,
                  },
                  assert.fail
                );
              };
  
              /**
               * ### .isOk(object, [message])
               *
               * Asserts that `object` is truthy.
               *
               *     assert.isOk('everything', 'everything is ok');
               *     assert.isOk(false, 'this will fail');
               *
               * @name isOk
               * @alias ok
               * @param {Mixed} object to test
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isOk = function (val, msg) {
                new Assertion(val, msg, assert.isOk, true).is.ok;
              };
  
              /**
               * ### .isNotOk(object, [message])
               *
               * Asserts that `object` is falsy.
               *
               *     assert.isNotOk('everything', 'this will fail');
               *     assert.isNotOk(false, 'this will pass');
               *
               * @name isNotOk
               * @alias notOk
               * @param {Mixed} object to test
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isNotOk = function (val, msg) {
                new Assertion(val, msg, assert.isNotOk, true).is.not.ok;
              };
  
              /**
               * ### .equal(actual, expected, [message])
               *
               * Asserts non-strict equality (`==`) of `actual` and `expected`.
               *
               *     assert.equal(3, '3', '== coerces values to strings');
               *
               * @name equal
               * @param {Mixed} actual
               * @param {Mixed} expected
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.equal = function (act, exp, msg) {
                var test = new Assertion(act, msg, assert.equal, true);
  
                test.assert(
                  exp == flag(test, 'object'),
                  'expected #{this} to equal #{exp}',
                  'expected #{this} to not equal #{act}',
                  exp,
                  act,
                  true
                );
              };
  
              /**
               * ### .notEqual(actual, expected, [message])
               *
               * Asserts non-strict inequality (`!=`) of `actual` and `expected`.
               *
               *     assert.notEqual(3, 4, 'these numbers are not equal');
               *
               * @name notEqual
               * @param {Mixed} actual
               * @param {Mixed} expected
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notEqual = function (act, exp, msg) {
                var test = new Assertion(act, msg, assert.notEqual, true);
  
                test.assert(
                  exp != flag(test, 'object'),
                  'expected #{this} to not equal #{exp}',
                  'expected #{this} to equal #{act}',
                  exp,
                  act,
                  true
                );
              };
  
              /**
               * ### .strictEqual(actual, expected, [message])
               *
               * Asserts strict equality (`===`) of `actual` and `expected`.
               *
               *     assert.strictEqual(true, true, 'these booleans are strictly equal');
               *
               * @name strictEqual
               * @param {Mixed} actual
               * @param {Mixed} expected
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.strictEqual = function (act, exp, msg) {
                new Assertion(act, msg, assert.strictEqual, true).to.equal(exp);
              };
  
              /**
               * ### .notStrictEqual(actual, expected, [message])
               *
               * Asserts strict inequality (`!==`) of `actual` and `expected`.
               *
               *     assert.notStrictEqual(3, '3', 'no coercion for strict equality');
               *
               * @name notStrictEqual
               * @param {Mixed} actual
               * @param {Mixed} expected
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notStrictEqual = function (act, exp, msg) {
                new Assertion(act, msg, assert.notStrictEqual, true).to.not.equal(exp);
              };
  
              /**
               * ### .deepEqual(actual, expected, [message])
               *
               * Asserts that `actual` is deeply equal to `expected`.
               *
               *     assert.deepEqual({ tea: 'green' }, { tea: 'green' });
               *
               * @name deepEqual
               * @param {Mixed} actual
               * @param {Mixed} expected
               * @param {String} message
               * @alias deepStrictEqual
               * @namespace Assert
               * @api public
               */
  
              assert.deepEqual = assert.deepStrictEqual = function (act, exp, msg) {
                new Assertion(act, msg, assert.deepEqual, true).to.eql(exp);
              };
  
              /**
               * ### .notDeepEqual(actual, expected, [message])
               *
               * Assert that `actual` is not deeply equal to `expected`.
               *
               *     assert.notDeepEqual({ tea: 'green' }, { tea: 'jasmine' });
               *
               * @name notDeepEqual
               * @param {Mixed} actual
               * @param {Mixed} expected
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notDeepEqual = function (act, exp, msg) {
                new Assertion(act, msg, assert.notDeepEqual, true).to.not.eql(exp);
              };
  
              /**
               * ### .isAbove(valueToCheck, valueToBeAbove, [message])
               *
               * Asserts `valueToCheck` is strictly greater than (>) `valueToBeAbove`.
               *
               *     assert.isAbove(5, 2, '5 is strictly greater than 2');
               *
               * @name isAbove
               * @param {Mixed} valueToCheck
               * @param {Mixed} valueToBeAbove
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isAbove = function (val, abv, msg) {
                new Assertion(val, msg, assert.isAbove, true).to.be.above(abv);
              };
  
              /**
               * ### .isAtLeast(valueToCheck, valueToBeAtLeast, [message])
               *
               * Asserts `valueToCheck` is greater than or equal to (>=) `valueToBeAtLeast`.
               *
               *     assert.isAtLeast(5, 2, '5 is greater or equal to 2');
               *     assert.isAtLeast(3, 3, '3 is greater or equal to 3');
               *
               * @name isAtLeast
               * @param {Mixed} valueToCheck
               * @param {Mixed} valueToBeAtLeast
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isAtLeast = function (val, atlst, msg) {
                new Assertion(val, msg, assert.isAtLeast, true).to.be.least(atlst);
              };
  
              /**
               * ### .isBelow(valueToCheck, valueToBeBelow, [message])
               *
               * Asserts `valueToCheck` is strictly less than (<) `valueToBeBelow`.
               *
               *     assert.isBelow(3, 6, '3 is strictly less than 6');
               *
               * @name isBelow
               * @param {Mixed} valueToCheck
               * @param {Mixed} valueToBeBelow
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isBelow = function (val, blw, msg) {
                new Assertion(val, msg, assert.isBelow, true).to.be.below(blw);
              };
  
              /**
               * ### .isAtMost(valueToCheck, valueToBeAtMost, [message])
               *
               * Asserts `valueToCheck` is less than or equal to (<=) `valueToBeAtMost`.
               *
               *     assert.isAtMost(3, 6, '3 is less than or equal to 6');
               *     assert.isAtMost(4, 4, '4 is less than or equal to 4');
               *
               * @name isAtMost
               * @param {Mixed} valueToCheck
               * @param {Mixed} valueToBeAtMost
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isAtMost = function (val, atmst, msg) {
                new Assertion(val, msg, assert.isAtMost, true).to.be.most(atmst);
              };
  
              /**
               * ### .isTrue(value, [message])
               *
               * Asserts that `value` is true.
               *
               *     var teaServed = true;
               *     assert.isTrue(teaServed, 'the tea has been served');
               *
               * @name isTrue
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isTrue = function (val, msg) {
                new Assertion(val, msg, assert.isTrue, true).is['true'];
              };
  
              /**
               * ### .isNotTrue(value, [message])
               *
               * Asserts that `value` is not true.
               *
               *     var tea = 'tasty chai';
               *     assert.isNotTrue(tea, 'great, time for tea!');
               *
               * @name isNotTrue
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isNotTrue = function (val, msg) {
                new Assertion(val, msg, assert.isNotTrue, true).to.not.equal(true);
              };
  
              /**
               * ### .isFalse(value, [message])
               *
               * Asserts that `value` is false.
               *
               *     var teaServed = false;
               *     assert.isFalse(teaServed, 'no tea yet? hmm...');
               *
               * @name isFalse
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isFalse = function (val, msg) {
                new Assertion(val, msg, assert.isFalse, true).is['false'];
              };
  
              /**
               * ### .isNotFalse(value, [message])
               *
               * Asserts that `value` is not false.
               *
               *     var tea = 'tasty chai';
               *     assert.isNotFalse(tea, 'great, time for tea!');
               *
               * @name isNotFalse
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isNotFalse = function (val, msg) {
                new Assertion(val, msg, assert.isNotFalse, true).to.not.equal(false);
              };
  
              /**
               * ### .isNull(value, [message])
               *
               * Asserts that `value` is null.
               *
               *     assert.isNull(err, 'there was no error');
               *
               * @name isNull
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isNull = function (val, msg) {
                new Assertion(val, msg, assert.isNull, true).to.equal(null);
              };
  
              /**
               * ### .isNotNull(value, [message])
               *
               * Asserts that `value` is not null.
               *
               *     var tea = 'tasty chai';
               *     assert.isNotNull(tea, 'great, time for tea!');
               *
               * @name isNotNull
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isNotNull = function (val, msg) {
                new Assertion(val, msg, assert.isNotNull, true).to.not.equal(null);
              };
  
              /**
               * ### .isNaN
               *
               * Asserts that value is NaN.
               *
               *     assert.isNaN(NaN, 'NaN is NaN');
               *
               * @name isNaN
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isNaN = function (val, msg) {
                new Assertion(val, msg, assert.isNaN, true).to.be.NaN;
              };
  
              /**
               * ### .isNotNaN
               *
               * Asserts that value is not NaN.
               *
               *     assert.isNotNaN(4, '4 is not NaN');
               *
               * @name isNotNaN
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
              assert.isNotNaN = function (val, msg) {
                new Assertion(val, msg, assert.isNotNaN, true).not.to.be.NaN;
              };
  
              /**
               * ### .exists
               *
               * Asserts that the target is neither `null` nor `undefined`.
               *
               *     var foo = 'hi';
               *
               *     assert.exists(foo, 'foo is neither `null` nor `undefined`');
               *
               * @name exists
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.exists = function (val, msg) {
                new Assertion(val, msg, assert.exists, true).to.exist;
              };
  
              /**
               * ### .notExists
               *
               * Asserts that the target is either `null` or `undefined`.
               *
               *     var bar = null
               *       , baz;
               *
               *     assert.notExists(bar);
               *     assert.notExists(baz, 'baz is either null or undefined');
               *
               * @name notExists
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notExists = function (val, msg) {
                new Assertion(val, msg, assert.notExists, true).to.not.exist;
              };
  
              /**
               * ### .isUndefined(value, [message])
               *
               * Asserts that `value` is `undefined`.
               *
               *     var tea;
               *     assert.isUndefined(tea, 'no tea defined');
               *
               * @name isUndefined
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isUndefined = function (val, msg) {
                new Assertion(val, msg, assert.isUndefined, true).to.equal(undefined);
              };
  
              /**
               * ### .isDefined(value, [message])
               *
               * Asserts that `value` is not `undefined`.
               *
               *     var tea = 'cup of chai';
               *     assert.isDefined(tea, 'tea has been defined');
               *
               * @name isDefined
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isDefined = function (val, msg) {
                new Assertion(val, msg, assert.isDefined, true).to.not.equal(undefined);
              };
  
              /**
               * ### .isFunction(value, [message])
               *
               * Asserts that `value` is a function.
               *
               *     function serveTea() { return 'cup of tea'; };
               *     assert.isFunction(serveTea, 'great, we can have tea now');
               *
               * @name isFunction
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isFunction = function (val, msg) {
                new Assertion(val, msg, assert.isFunction, true).to.be.a('function');
              };
  
              /**
               * ### .isNotFunction(value, [message])
               *
               * Asserts that `value` is _not_ a function.
               *
               *     var serveTea = [ 'heat', 'pour', 'sip' ];
               *     assert.isNotFunction(serveTea, 'great, we have listed the steps');
               *
               * @name isNotFunction
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isNotFunction = function (val, msg) {
                new Assertion(val, msg, assert.isNotFunction, true).to.not.be.a('function');
              };
  
              /**
               * ### .isObject(value, [message])
               *
               * Asserts that `value` is an object of type 'Object' (as revealed by `Object.prototype.toString`).
               * _The assertion does not match subclassed objects._
               *
               *     var selection = { name: 'Chai', serve: 'with spices' };
               *     assert.isObject(selection, 'tea selection is an object');
               *
               * @name isObject
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isObject = function (val, msg) {
                new Assertion(val, msg, assert.isObject, true).to.be.a('object');
              };
  
              /**
               * ### .isNotObject(value, [message])
               *
               * Asserts that `value` is _not_ an object of type 'Object' (as revealed by `Object.prototype.toString`).
               *
               *     var selection = 'chai'
               *     assert.isNotObject(selection, 'tea selection is not an object');
               *     assert.isNotObject(null, 'null is not an object');
               *
               * @name isNotObject
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isNotObject = function (val, msg) {
                new Assertion(val, msg, assert.isNotObject, true).to.not.be.a('object');
              };
  
              /**
               * ### .isArray(value, [message])
               *
               * Asserts that `value` is an array.
               *
               *     var menu = [ 'green', 'chai', 'oolong' ];
               *     assert.isArray(menu, 'what kind of tea do we want?');
               *
               * @name isArray
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isArray = function (val, msg) {
                new Assertion(val, msg, assert.isArray, true).to.be.an('array');
              };
  
              /**
               * ### .isNotArray(value, [message])
               *
               * Asserts that `value` is _not_ an array.
               *
               *     var menu = 'green|chai|oolong';
               *     assert.isNotArray(menu, 'what kind of tea do we want?');
               *
               * @name isNotArray
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isNotArray = function (val, msg) {
                new Assertion(val, msg, assert.isNotArray, true).to.not.be.an('array');
              };
  
              /**
               * ### .isString(value, [message])
               *
               * Asserts that `value` is a string.
               *
               *     var teaOrder = 'chai';
               *     assert.isString(teaOrder, 'order placed');
               *
               * @name isString
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isString = function (val, msg) {
                new Assertion(val, msg, assert.isString, true).to.be.a('string');
              };
  
              /**
               * ### .isNotString(value, [message])
               *
               * Asserts that `value` is _not_ a string.
               *
               *     var teaOrder = 4;
               *     assert.isNotString(teaOrder, 'order placed');
               *
               * @name isNotString
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isNotString = function (val, msg) {
                new Assertion(val, msg, assert.isNotString, true).to.not.be.a('string');
              };
  
              /**
               * ### .isNumber(value, [message])
               *
               * Asserts that `value` is a number.
               *
               *     var cups = 2;
               *     assert.isNumber(cups, 'how many cups');
               *
               * @name isNumber
               * @param {Number} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isNumber = function (val, msg) {
                new Assertion(val, msg, assert.isNumber, true).to.be.a('number');
              };
  
              /**
               * ### .isNotNumber(value, [message])
               *
               * Asserts that `value` is _not_ a number.
               *
               *     var cups = '2 cups please';
               *     assert.isNotNumber(cups, 'how many cups');
               *
               * @name isNotNumber
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isNotNumber = function (val, msg) {
                new Assertion(val, msg, assert.isNotNumber, true).to.not.be.a('number');
              };
  
              /**
               * ### .isFinite(value, [message])
               *
               * Asserts that `value` is a finite number. Unlike `.isNumber`, this will fail for `NaN` and `Infinity`.
               *
               *     var cups = 2;
               *     assert.isFinite(cups, 'how many cups');
               *
               *     assert.isFinite(NaN); // throws
               *
               * @name isFinite
               * @param {Number} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isFinite = function (val, msg) {
                new Assertion(val, msg, assert.isFinite, true).to.be.finite;
              };
  
              /**
               * ### .isBoolean(value, [message])
               *
               * Asserts that `value` is a boolean.
               *
               *     var teaReady = true
               *       , teaServed = false;
               *
               *     assert.isBoolean(teaReady, 'is the tea ready');
               *     assert.isBoolean(teaServed, 'has tea been served');
               *
               * @name isBoolean
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isBoolean = function (val, msg) {
                new Assertion(val, msg, assert.isBoolean, true).to.be.a('boolean');
              };
  
              /**
               * ### .isNotBoolean(value, [message])
               *
               * Asserts that `value` is _not_ a boolean.
               *
               *     var teaReady = 'yep'
               *       , teaServed = 'nope';
               *
               *     assert.isNotBoolean(teaReady, 'is the tea ready');
               *     assert.isNotBoolean(teaServed, 'has tea been served');
               *
               * @name isNotBoolean
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.isNotBoolean = function (val, msg) {
                new Assertion(val, msg, assert.isNotBoolean, true).to.not.be.a('boolean');
              };
  
              /**
               * ### .typeOf(value, name, [message])
               *
               * Asserts that `value`'s type is `name`, as determined by
               * `Object.prototype.toString`.
               *
               *     assert.typeOf({ tea: 'chai' }, 'object', 'we have an object');
               *     assert.typeOf(['chai', 'jasmine'], 'array', 'we have an array');
               *     assert.typeOf('tea', 'string', 'we have a string');
               *     assert.typeOf(/tea/, 'regexp', 'we have a regular expression');
               *     assert.typeOf(null, 'null', 'we have a null');
               *     assert.typeOf(undefined, 'undefined', 'we have an undefined');
               *
               * @name typeOf
               * @param {Mixed} value
               * @param {String} name
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.typeOf = function (val, type, msg) {
                new Assertion(val, msg, assert.typeOf, true).to.be.a(type);
              };
  
              /**
               * ### .notTypeOf(value, name, [message])
               *
               * Asserts that `value`'s type is _not_ `name`, as determined by
               * `Object.prototype.toString`.
               *
               *     assert.notTypeOf('tea', 'number', 'strings are not numbers');
               *
               * @name notTypeOf
               * @param {Mixed} value
               * @param {String} typeof name
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notTypeOf = function (val, type, msg) {
                new Assertion(val, msg, assert.notTypeOf, true).to.not.be.a(type);
              };
  
              /**
               * ### .instanceOf(object, constructor, [message])
               *
               * Asserts that `value` is an instance of `constructor`.
               *
               *     var Tea = function (name) { this.name = name; }
               *       , chai = new Tea('chai');
               *
               *     assert.instanceOf(chai, Tea, 'chai is an instance of tea');
               *
               * @name instanceOf
               * @param {Object} object
               * @param {Constructor} constructor
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.instanceOf = function (val, type, msg) {
                new Assertion(val, msg, assert.instanceOf, true).to.be.instanceOf(type);
              };
  
              /**
               * ### .notInstanceOf(object, constructor, [message])
               *
               * Asserts `value` is not an instance of `constructor`.
               *
               *     var Tea = function (name) { this.name = name; }
               *       , chai = new String('chai');
               *
               *     assert.notInstanceOf(chai, Tea, 'chai is not an instance of tea');
               *
               * @name notInstanceOf
               * @param {Object} object
               * @param {Constructor} constructor
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notInstanceOf = function (val, type, msg) {
                new Assertion(val, msg, assert.notInstanceOf, true).to.not.be.instanceOf(type);
              };
  
              /**
               * ### .include(haystack, needle, [message])
               *
               * Asserts that `haystack` includes `needle`. Can be used to assert the
               * inclusion of a value in an array, a substring in a string, or a subset of
               * properties in an object.
               *
               *     assert.include([1,2,3], 2, 'array contains value');
               *     assert.include('foobar', 'foo', 'string contains substring');
               *     assert.include({ foo: 'bar', hello: 'universe' }, { foo: 'bar' }, 'object contains property');
               *
               * Strict equality (===) is used. When asserting the inclusion of a value in
               * an array, the array is searched for an element that's strictly equal to the
               * given value. When asserting a subset of properties in an object, the object
               * is searched for the given property keys, checking that each one is present
               * and strictly equal to the given property value. For instance:
               *
               *     var obj1 = {a: 1}
               *       , obj2 = {b: 2};
               *     assert.include([obj1, obj2], obj1);
               *     assert.include({foo: obj1, bar: obj2}, {foo: obj1});
               *     assert.include({foo: obj1, bar: obj2}, {foo: obj1, bar: obj2});
               *
               * @name include
               * @param {Array|String} haystack
               * @param {Mixed} needle
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.include = function (exp, inc, msg) {
                new Assertion(exp, msg, assert.include, true).include(inc);
              };
  
              /**
               * ### .notInclude(haystack, needle, [message])
               *
               * Asserts that `haystack` does not include `needle`. Can be used to assert
               * the absence of a value in an array, a substring in a string, or a subset of
               * properties in an object.
               *
               *     assert.notInclude([1,2,3], 4, "array doesn't contain value");
               *     assert.notInclude('foobar', 'baz', "string doesn't contain substring");
               *     assert.notInclude({ foo: 'bar', hello: 'universe' }, { foo: 'baz' }, 'object doesn't contain property');
               *
               * Strict equality (===) is used. When asserting the absence of a value in an
               * array, the array is searched to confirm the absence of an element that's
               * strictly equal to the given value. When asserting a subset of properties in
               * an object, the object is searched to confirm that at least one of the given
               * property keys is either not present or not strictly equal to the given
               * property value. For instance:
               *
               *     var obj1 = {a: 1}
               *       , obj2 = {b: 2};
               *     assert.notInclude([obj1, obj2], {a: 1});
               *     assert.notInclude({foo: obj1, bar: obj2}, {foo: {a: 1}});
               *     assert.notInclude({foo: obj1, bar: obj2}, {foo: obj1, bar: {b: 2}});
               *
               * @name notInclude
               * @param {Array|String} haystack
               * @param {Mixed} needle
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notInclude = function (exp, inc, msg) {
                new Assertion(exp, msg, assert.notInclude, true).not.include(inc);
              };
  
              /**
               * ### .deepInclude(haystack, needle, [message])
               *
               * Asserts that `haystack` includes `needle`. Can be used to assert the
               * inclusion of a value in an array or a subset of properties in an object.
               * Deep equality is used.
               *
               *     var obj1 = {a: 1}
               *       , obj2 = {b: 2};
               *     assert.deepInclude([obj1, obj2], {a: 1});
               *     assert.deepInclude({foo: obj1, bar: obj2}, {foo: {a: 1}});
               *     assert.deepInclude({foo: obj1, bar: obj2}, {foo: {a: 1}, bar: {b: 2}});
               *
               * @name deepInclude
               * @param {Array|String} haystack
               * @param {Mixed} needle
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.deepInclude = function (exp, inc, msg) {
                new Assertion(exp, msg, assert.deepInclude, true).deep.include(inc);
              };
  
              /**
               * ### .notDeepInclude(haystack, needle, [message])
               *
               * Asserts that `haystack` does not include `needle`. Can be used to assert
               * the absence of a value in an array or a subset of properties in an object.
               * Deep equality is used.
               *
               *     var obj1 = {a: 1}
               *       , obj2 = {b: 2};
               *     assert.notDeepInclude([obj1, obj2], {a: 9});
               *     assert.notDeepInclude({foo: obj1, bar: obj2}, {foo: {a: 9}});
               *     assert.notDeepInclude({foo: obj1, bar: obj2}, {foo: {a: 1}, bar: {b: 9}});
               *
               * @name notDeepInclude
               * @param {Array|String} haystack
               * @param {Mixed} needle
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notDeepInclude = function (exp, inc, msg) {
                new Assertion(exp, msg, assert.notDeepInclude, true).not.deep.include(inc);
              };
  
              /**
               * ### .nestedInclude(haystack, needle, [message])
               *
               * Asserts that 'haystack' includes 'needle'.
               * Can be used to assert the inclusion of a subset of properties in an
               * object.
               * Enables the use of dot- and bracket-notation for referencing nested
               * properties.
               * '[]' and '.' in property names can be escaped using double backslashes.
               *
               *     assert.nestedInclude({'.a': {'b': 'x'}}, {'\\.a.[b]': 'x'});
               *     assert.nestedInclude({'a': {'[b]': 'x'}}, {'a.\\[b\\]': 'x'});
               *
               * @name nestedInclude
               * @param {Object} haystack
               * @param {Object} needle
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.nestedInclude = function (exp, inc, msg) {
                new Assertion(exp, msg, assert.nestedInclude, true).nested.include(inc);
              };
  
              /**
               * ### .notNestedInclude(haystack, needle, [message])
               *
               * Asserts that 'haystack' does not include 'needle'.
               * Can be used to assert the absence of a subset of properties in an
               * object.
               * Enables the use of dot- and bracket-notation for referencing nested
               * properties.
               * '[]' and '.' in property names can be escaped using double backslashes.
               *
               *     assert.notNestedInclude({'.a': {'b': 'x'}}, {'\\.a.b': 'y'});
               *     assert.notNestedInclude({'a': {'[b]': 'x'}}, {'a.\\[b\\]': 'y'});
               *
               * @name notNestedInclude
               * @param {Object} haystack
               * @param {Object} needle
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notNestedInclude = function (exp, inc, msg) {
                new Assertion(exp, msg, assert.notNestedInclude, true).not.nested.include(inc);
              };
  
              /**
               * ### .deepNestedInclude(haystack, needle, [message])
               *
               * Asserts that 'haystack' includes 'needle'.
               * Can be used to assert the inclusion of a subset of properties in an
               * object while checking for deep equality.
               * Enables the use of dot- and bracket-notation for referencing nested
               * properties.
               * '[]' and '.' in property names can be escaped using double backslashes.
               *
               *     assert.deepNestedInclude({a: {b: [{x: 1}]}}, {'a.b[0]': {x: 1}});
               *     assert.deepNestedInclude({'.a': {'[b]': {x: 1}}}, {'\\.a.\\[b\\]': {x: 1}});
               *
               * @name deepNestedInclude
               * @param {Object} haystack
               * @param {Object} needle
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.deepNestedInclude = function (exp, inc, msg) {
                new Assertion(exp, msg, assert.deepNestedInclude, true).deep.nested.include(inc);
              };
  
              /**
               * ### .notDeepNestedInclude(haystack, needle, [message])
               *
               * Asserts that 'haystack' does not include 'needle'.
               * Can be used to assert the absence of a subset of properties in an
               * object while checking for deep equality.
               * Enables the use of dot- and bracket-notation for referencing nested
               * properties.
               * '[]' and '.' in property names can be escaped using double backslashes.
               *
               *     assert.notDeepNestedInclude({a: {b: [{x: 1}]}}, {'a.b[0]': {y: 1}})
               *     assert.notDeepNestedInclude({'.a': {'[b]': {x: 1}}}, {'\\.a.\\[b\\]': {y: 2}});
               *
               * @name notDeepNestedInclude
               * @param {Object} haystack
               * @param {Object} needle
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notDeepNestedInclude = function (exp, inc, msg) {
                new Assertion(exp, msg, assert.notDeepNestedInclude, true).not.deep.nested.include(
                  inc
                );
              };
  
              /**
               * ### .ownInclude(haystack, needle, [message])
               *
               * Asserts that 'haystack' includes 'needle'.
               * Can be used to assert the inclusion of a subset of properties in an
               * object while ignoring inherited properties.
               *
               *     assert.ownInclude({ a: 1 }, { a: 1 });
               *
               * @name ownInclude
               * @param {Object} haystack
               * @param {Object} needle
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.ownInclude = function (exp, inc, msg) {
                new Assertion(exp, msg, assert.ownInclude, true).own.include(inc);
              };
  
              /**
               * ### .notOwnInclude(haystack, needle, [message])
               *
               * Asserts that 'haystack' includes 'needle'.
               * Can be used to assert the absence of a subset of properties in an
               * object while ignoring inherited properties.
               *
               *     Object.prototype.b = 2;
               *
               *     assert.notOwnInclude({ a: 1 }, { b: 2 });
               *
               * @name notOwnInclude
               * @param {Object} haystack
               * @param {Object} needle
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notOwnInclude = function (exp, inc, msg) {
                new Assertion(exp, msg, assert.notOwnInclude, true).not.own.include(inc);
              };
  
              /**
               * ### .deepOwnInclude(haystack, needle, [message])
               *
               * Asserts that 'haystack' includes 'needle'.
               * Can be used to assert the inclusion of a subset of properties in an
               * object while ignoring inherited properties and checking for deep equality.
               *
               *      assert.deepOwnInclude({a: {b: 2}}, {a: {b: 2}});
               *
               * @name deepOwnInclude
               * @param {Object} haystack
               * @param {Object} needle
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.deepOwnInclude = function (exp, inc, msg) {
                new Assertion(exp, msg, assert.deepOwnInclude, true).deep.own.include(inc);
              };
  
              /**
               * ### .notDeepOwnInclude(haystack, needle, [message])
               *
               * Asserts that 'haystack' includes 'needle'.
               * Can be used to assert the absence of a subset of properties in an
               * object while ignoring inherited properties and checking for deep equality.
               *
               *      assert.notDeepOwnInclude({a: {b: 2}}, {a: {c: 3}});
               *
               * @name notDeepOwnInclude
               * @param {Object} haystack
               * @param {Object} needle
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notDeepOwnInclude = function (exp, inc, msg) {
                new Assertion(exp, msg, assert.notDeepOwnInclude, true).not.deep.own.include(inc);
              };
  
              /**
               * ### .match(value, regexp, [message])
               *
               * Asserts that `value` matches the regular expression `regexp`.
               *
               *     assert.match('foobar', /^foo/, 'regexp matches');
               *
               * @name match
               * @param {Mixed} value
               * @param {RegExp} regexp
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.match = function (exp, re, msg) {
                new Assertion(exp, msg, assert.match, true).to.match(re);
              };
  
              /**
               * ### .notMatch(value, regexp, [message])
               *
               * Asserts that `value` does not match the regular expression `regexp`.
               *
               *     assert.notMatch('foobar', /^foo/, 'regexp does not match');
               *
               * @name notMatch
               * @param {Mixed} value
               * @param {RegExp} regexp
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notMatch = function (exp, re, msg) {
                new Assertion(exp, msg, assert.notMatch, true).to.not.match(re);
              };
  
              /**
               * ### .property(object, property, [message])
               *
               * Asserts that `object` has a direct or inherited property named by
               * `property`.
               *
               *     assert.property({ tea: { green: 'matcha' }}, 'tea');
               *     assert.property({ tea: { green: 'matcha' }}, 'toString');
               *
               * @name property
               * @param {Object} object
               * @param {String} property
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.property = function (obj, prop, msg) {
                new Assertion(obj, msg, assert.property, true).to.have.property(prop);
              };
  
              /**
               * ### .notProperty(object, property, [message])
               *
               * Asserts that `object` does _not_ have a direct or inherited property named
               * by `property`.
               *
               *     assert.notProperty({ tea: { green: 'matcha' }}, 'coffee');
               *
               * @name notProperty
               * @param {Object} object
               * @param {String} property
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notProperty = function (obj, prop, msg) {
                new Assertion(obj, msg, assert.notProperty, true).to.not.have.property(prop);
              };
  
              /**
               * ### .propertyVal(object, property, value, [message])
               *
               * Asserts that `object` has a direct or inherited property named by
               * `property` with a value given by `value`. Uses a strict equality check
               * (===).
               *
               *     assert.propertyVal({ tea: 'is good' }, 'tea', 'is good');
               *
               * @name propertyVal
               * @param {Object} object
               * @param {String} property
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.propertyVal = function (obj, prop, val, msg) {
                new Assertion(obj, msg, assert.propertyVal, true).to.have.property(prop, val);
              };
  
              /**
               * ### .notPropertyVal(object, property, value, [message])
               *
               * Asserts that `object` does _not_ have a direct or inherited property named
               * by `property` with value given by `value`. Uses a strict equality check
               * (===).
               *
               *     assert.notPropertyVal({ tea: 'is good' }, 'tea', 'is bad');
               *     assert.notPropertyVal({ tea: 'is good' }, 'coffee', 'is good');
               *
               * @name notPropertyVal
               * @param {Object} object
               * @param {String} property
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notPropertyVal = function (obj, prop, val, msg) {
                new Assertion(obj, msg, assert.notPropertyVal, true).to.not.have.property(prop, val);
              };
  
              /**
               * ### .deepPropertyVal(object, property, value, [message])
               *
               * Asserts that `object` has a direct or inherited property named by
               * `property` with a value given by `value`. Uses a deep equality check.
               *
               *     assert.deepPropertyVal({ tea: { green: 'matcha' } }, 'tea', { green: 'matcha' });
               *
               * @name deepPropertyVal
               * @param {Object} object
               * @param {String} property
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.deepPropertyVal = function (obj, prop, val, msg) {
                new Assertion(obj, msg, assert.deepPropertyVal, true).to.have.deep.property(
                  prop,
                  val
                );
              };
  
              /**
               * ### .notDeepPropertyVal(object, property, value, [message])
               *
               * Asserts that `object` does _not_ have a direct or inherited property named
               * by `property` with value given by `value`. Uses a deep equality check.
               *
               *     assert.notDeepPropertyVal({ tea: { green: 'matcha' } }, 'tea', { black: 'matcha' });
               *     assert.notDeepPropertyVal({ tea: { green: 'matcha' } }, 'tea', { green: 'oolong' });
               *     assert.notDeepPropertyVal({ tea: { green: 'matcha' } }, 'coffee', { green: 'matcha' });
               *
               * @name notDeepPropertyVal
               * @param {Object} object
               * @param {String} property
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notDeepPropertyVal = function (obj, prop, val, msg) {
                new Assertion(obj, msg, assert.notDeepPropertyVal, true).to.not.have.deep.property(
                  prop,
                  val
                );
              };
  
              /**
               * ### .ownProperty(object, property, [message])
               *
               * Asserts that `object` has a direct property named by `property`. Inherited
               * properties aren't checked.
               *
               *     assert.ownProperty({ tea: { green: 'matcha' }}, 'tea');
               *
               * @name ownProperty
               * @param {Object} object
               * @param {String} property
               * @param {String} message
               * @api public
               */
  
              assert.ownProperty = function (obj, prop, msg) {
                new Assertion(obj, msg, assert.ownProperty, true).to.have.own.property(prop);
              };
  
              /**
               * ### .notOwnProperty(object, property, [message])
               *
               * Asserts that `object` does _not_ have a direct property named by
               * `property`. Inherited properties aren't checked.
               *
               *     assert.notOwnProperty({ tea: { green: 'matcha' }}, 'coffee');
               *     assert.notOwnProperty({}, 'toString');
               *
               * @name notOwnProperty
               * @param {Object} object
               * @param {String} property
               * @param {String} message
               * @api public
               */
  
              assert.notOwnProperty = function (obj, prop, msg) {
                new Assertion(obj, msg, assert.notOwnProperty, true).to.not.have.own.property(prop);
              };
  
              /**
               * ### .ownPropertyVal(object, property, value, [message])
               *
               * Asserts that `object` has a direct property named by `property` and a value
               * equal to the provided `value`. Uses a strict equality check (===).
               * Inherited properties aren't checked.
               *
               *     assert.ownPropertyVal({ coffee: 'is good'}, 'coffee', 'is good');
               *
               * @name ownPropertyVal
               * @param {Object} object
               * @param {String} property
               * @param {Mixed} value
               * @param {String} message
               * @api public
               */
  
              assert.ownPropertyVal = function (obj, prop, value, msg) {
                new Assertion(obj, msg, assert.ownPropertyVal, true).to.have.own.property(
                  prop,
                  value
                );
              };
  
              /**
               * ### .notOwnPropertyVal(object, property, value, [message])
               *
               * Asserts that `object` does _not_ have a direct property named by `property`
               * with a value equal to the provided `value`. Uses a strict equality check
               * (===). Inherited properties aren't checked.
               *
               *     assert.notOwnPropertyVal({ tea: 'is better'}, 'tea', 'is worse');
               *     assert.notOwnPropertyVal({}, 'toString', Object.prototype.toString);
               *
               * @name notOwnPropertyVal
               * @param {Object} object
               * @param {String} property
               * @param {Mixed} value
               * @param {String} message
               * @api public
               */
  
              assert.notOwnPropertyVal = function (obj, prop, value, msg) {
                new Assertion(obj, msg, assert.notOwnPropertyVal, true).to.not.have.own.property(
                  prop,
                  value
                );
              };
  
              /**
               * ### .deepOwnPropertyVal(object, property, value, [message])
               *
               * Asserts that `object` has a direct property named by `property` and a value
               * equal to the provided `value`. Uses a deep equality check. Inherited
               * properties aren't checked.
               *
               *     assert.deepOwnPropertyVal({ tea: { green: 'matcha' } }, 'tea', { green: 'matcha' });
               *
               * @name deepOwnPropertyVal
               * @param {Object} object
               * @param {String} property
               * @param {Mixed} value
               * @param {String} message
               * @api public
               */
  
              assert.deepOwnPropertyVal = function (obj, prop, value, msg) {
                new Assertion(obj, msg, assert.deepOwnPropertyVal, true).to.have.deep.own.property(
                  prop,
                  value
                );
              };
  
              /**
               * ### .notDeepOwnPropertyVal(object, property, value, [message])
               *
               * Asserts that `object` does _not_ have a direct property named by `property`
               * with a value equal to the provided `value`. Uses a deep equality check.
               * Inherited properties aren't checked.
               *
               *     assert.notDeepOwnPropertyVal({ tea: { green: 'matcha' } }, 'tea', { black: 'matcha' });
               *     assert.notDeepOwnPropertyVal({ tea: { green: 'matcha' } }, 'tea', { green: 'oolong' });
               *     assert.notDeepOwnPropertyVal({ tea: { green: 'matcha' } }, 'coffee', { green: 'matcha' });
               *     assert.notDeepOwnPropertyVal({}, 'toString', Object.prototype.toString);
               *
               * @name notDeepOwnPropertyVal
               * @param {Object} object
               * @param {String} property
               * @param {Mixed} value
               * @param {String} message
               * @api public
               */
  
              assert.notDeepOwnPropertyVal = function (obj, prop, value, msg) {
                new Assertion(
                  obj,
                  msg,
                  assert.notDeepOwnPropertyVal,
                  true
                ).to.not.have.deep.own.property(prop, value);
              };
  
              /**
               * ### .nestedProperty(object, property, [message])
               *
               * Asserts that `object` has a direct or inherited property named by
               * `property`, which can be a string using dot- and bracket-notation for
               * nested reference.
               *
               *     assert.nestedProperty({ tea: { green: 'matcha' }}, 'tea.green');
               *
               * @name nestedProperty
               * @param {Object} object
               * @param {String} property
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.nestedProperty = function (obj, prop, msg) {
                new Assertion(obj, msg, assert.nestedProperty, true).to.have.nested.property(prop);
              };
  
              /**
               * ### .notNestedProperty(object, property, [message])
               *
               * Asserts that `object` does _not_ have a property named by `property`, which
               * can be a string using dot- and bracket-notation for nested reference. The
               * property cannot exist on the object nor anywhere in its prototype chain.
               *
               *     assert.notNestedProperty({ tea: { green: 'matcha' }}, 'tea.oolong');
               *
               * @name notNestedProperty
               * @param {Object} object
               * @param {String} property
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notNestedProperty = function (obj, prop, msg) {
                new Assertion(obj, msg, assert.notNestedProperty, true).to.not.have.nested.property(
                  prop
                );
              };
  
              /**
               * ### .nestedPropertyVal(object, property, value, [message])
               *
               * Asserts that `object` has a property named by `property` with value given
               * by `value`. `property` can use dot- and bracket-notation for nested
               * reference. Uses a strict equality check (===).
               *
               *     assert.nestedPropertyVal({ tea: { green: 'matcha' }}, 'tea.green', 'matcha');
               *
               * @name nestedPropertyVal
               * @param {Object} object
               * @param {String} property
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.nestedPropertyVal = function (obj, prop, val, msg) {
                new Assertion(obj, msg, assert.nestedPropertyVal, true).to.have.nested.property(
                  prop,
                  val
                );
              };
  
              /**
               * ### .notNestedPropertyVal(object, property, value, [message])
               *
               * Asserts that `object` does _not_ have a property named by `property` with
               * value given by `value`. `property` can use dot- and bracket-notation for
               * nested reference. Uses a strict equality check (===).
               *
               *     assert.notNestedPropertyVal({ tea: { green: 'matcha' }}, 'tea.green', 'konacha');
               *     assert.notNestedPropertyVal({ tea: { green: 'matcha' }}, 'coffee.green', 'matcha');
               *
               * @name notNestedPropertyVal
               * @param {Object} object
               * @param {String} property
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notNestedPropertyVal = function (obj, prop, val, msg) {
                new Assertion(
                  obj,
                  msg,
                  assert.notNestedPropertyVal,
                  true
                ).to.not.have.nested.property(prop, val);
              };
  
              /**
               * ### .deepNestedPropertyVal(object, property, value, [message])
               *
               * Asserts that `object` has a property named by `property` with a value given
               * by `value`. `property` can use dot- and bracket-notation for nested
               * reference. Uses a deep equality check.
               *
               *     assert.deepNestedPropertyVal({ tea: { green: { matcha: 'yum' } } }, 'tea.green', { matcha: 'yum' });
               *
               * @name deepNestedPropertyVal
               * @param {Object} object
               * @param {String} property
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.deepNestedPropertyVal = function (obj, prop, val, msg) {
                new Assertion(
                  obj,
                  msg,
                  assert.deepNestedPropertyVal,
                  true
                ).to.have.deep.nested.property(prop, val);
              };
  
              /**
               * ### .notDeepNestedPropertyVal(object, property, value, [message])
               *
               * Asserts that `object` does _not_ have a property named by `property` with
               * value given by `value`. `property` can use dot- and bracket-notation for
               * nested reference. Uses a deep equality check.
               *
               *     assert.notDeepNestedPropertyVal({ tea: { green: { matcha: 'yum' } } }, 'tea.green', { oolong: 'yum' });
               *     assert.notDeepNestedPropertyVal({ tea: { green: { matcha: 'yum' } } }, 'tea.green', { matcha: 'yuck' });
               *     assert.notDeepNestedPropertyVal({ tea: { green: { matcha: 'yum' } } }, 'tea.black', { matcha: 'yum' });
               *
               * @name notDeepNestedPropertyVal
               * @param {Object} object
               * @param {String} property
               * @param {Mixed} value
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notDeepNestedPropertyVal = function (obj, prop, val, msg) {
                new Assertion(
                  obj,
                  msg,
                  assert.notDeepNestedPropertyVal,
                  true
                ).to.not.have.deep.nested.property(prop, val);
              };
  
              /**
               * ### .lengthOf(object, length, [message])
               *
               * Asserts that `object` has a `length` or `size` with the expected value.
               *
               *     assert.lengthOf([1,2,3], 3, 'array has length of 3');
               *     assert.lengthOf('foobar', 6, 'string has length of 6');
               *     assert.lengthOf(new Set([1,2,3]), 3, 'set has size of 3');
               *     assert.lengthOf(new Map([['a',1],['b',2],['c',3]]), 3, 'map has size of 3');
               *
               * @name lengthOf
               * @param {Mixed} object
               * @param {Number} length
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.lengthOf = function (exp, len, msg) {
                new Assertion(exp, msg, assert.lengthOf, true).to.have.lengthOf(len);
              };
  
              /**
               * ### .hasAnyKeys(object, [keys], [message])
               *
               * Asserts that `object` has at least one of the `keys` provided.
               * You can also provide a single object instead of a `keys` array and its keys
               * will be used as the expected set of keys.
               *
               *     assert.hasAnyKeys({foo: 1, bar: 2, baz: 3}, ['foo', 'iDontExist', 'baz']);
               *     assert.hasAnyKeys({foo: 1, bar: 2, baz: 3}, {foo: 30, iDontExist: 99, baz: 1337});
               *     assert.hasAnyKeys(new Map([[{foo: 1}, 'bar'], ['key', 'value']]), [{foo: 1}, 'key']);
               *     assert.hasAnyKeys(new Set([{foo: 'bar'}, 'anotherKey']), [{foo: 'bar'}, 'anotherKey']);
               *
               * @name hasAnyKeys
               * @param {Mixed} object
               * @param {Array|Object} keys
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.hasAnyKeys = function (obj, keys, msg) {
                new Assertion(obj, msg, assert.hasAnyKeys, true).to.have.any.keys(keys);
              };
  
              /**
               * ### .hasAllKeys(object, [keys], [message])
               *
               * Asserts that `object` has all and only all of the `keys` provided.
               * You can also provide a single object instead of a `keys` array and its keys
               * will be used as the expected set of keys.
               *
               *     assert.hasAllKeys({foo: 1, bar: 2, baz: 3}, ['foo', 'bar', 'baz']);
               *     assert.hasAllKeys({foo: 1, bar: 2, baz: 3}, {foo: 30, bar: 99, baz: 1337]);
               *     assert.hasAllKeys(new Map([[{foo: 1}, 'bar'], ['key', 'value']]), [{foo: 1}, 'key']);
               *     assert.hasAllKeys(new Set([{foo: 'bar'}, 'anotherKey'], [{foo: 'bar'}, 'anotherKey']);
               *
               * @name hasAllKeys
               * @param {Mixed} object
               * @param {String[]} keys
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.hasAllKeys = function (obj, keys, msg) {
                new Assertion(obj, msg, assert.hasAllKeys, true).to.have.all.keys(keys);
              };
  
              /**
               * ### .containsAllKeys(object, [keys], [message])
               *
               * Asserts that `object` has all of the `keys` provided but may have more keys not listed.
               * You can also provide a single object instead of a `keys` array and its keys
               * will be used as the expected set of keys.
               *
               *     assert.containsAllKeys({foo: 1, bar: 2, baz: 3}, ['foo', 'baz']);
               *     assert.containsAllKeys({foo: 1, bar: 2, baz: 3}, ['foo', 'bar', 'baz']);
               *     assert.containsAllKeys({foo: 1, bar: 2, baz: 3}, {foo: 30, baz: 1337});
               *     assert.containsAllKeys({foo: 1, bar: 2, baz: 3}, {foo: 30, bar: 99, baz: 1337});
               *     assert.containsAllKeys(new Map([[{foo: 1}, 'bar'], ['key', 'value']]), [{foo: 1}]);
               *     assert.containsAllKeys(new Map([[{foo: 1}, 'bar'], ['key', 'value']]), [{foo: 1}, 'key']);
               *     assert.containsAllKeys(new Set([{foo: 'bar'}, 'anotherKey'], [{foo: 'bar'}]);
               *     assert.containsAllKeys(new Set([{foo: 'bar'}, 'anotherKey'], [{foo: 'bar'}, 'anotherKey']);
               *
               * @name containsAllKeys
               * @param {Mixed} object
               * @param {String[]} keys
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.containsAllKeys = function (obj, keys, msg) {
                new Assertion(obj, msg, assert.containsAllKeys, true).to.contain.all.keys(keys);
              };
  
              /**
               * ### .doesNotHaveAnyKeys(object, [keys], [message])
               *
               * Asserts that `object` has none of the `keys` provided.
               * You can also provide a single object instead of a `keys` array and its keys
               * will be used as the expected set of keys.
               *
               *     assert.doesNotHaveAnyKeys({foo: 1, bar: 2, baz: 3}, ['one', 'two', 'example']);
               *     assert.doesNotHaveAnyKeys({foo: 1, bar: 2, baz: 3}, {one: 1, two: 2, example: 'foo'});
               *     assert.doesNotHaveAnyKeys(new Map([[{foo: 1}, 'bar'], ['key', 'value']]), [{one: 'two'}, 'example']);
               *     assert.doesNotHaveAnyKeys(new Set([{foo: 'bar'}, 'anotherKey'], [{one: 'two'}, 'example']);
               *
               * @name doesNotHaveAnyKeys
               * @param {Mixed} object
               * @param {String[]} keys
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.doesNotHaveAnyKeys = function (obj, keys, msg) {
                new Assertion(obj, msg, assert.doesNotHaveAnyKeys, true).to.not.have.any.keys(keys);
              };
  
              /**
               * ### .doesNotHaveAllKeys(object, [keys], [message])
               *
               * Asserts that `object` does not have at least one of the `keys` provided.
               * You can also provide a single object instead of a `keys` array and its keys
               * will be used as the expected set of keys.
               *
               *     assert.doesNotHaveAllKeys({foo: 1, bar: 2, baz: 3}, ['one', 'two', 'example']);
               *     assert.doesNotHaveAllKeys({foo: 1, bar: 2, baz: 3}, {one: 1, two: 2, example: 'foo'});
               *     assert.doesNotHaveAllKeys(new Map([[{foo: 1}, 'bar'], ['key', 'value']]), [{one: 'two'}, 'example']);
               *     assert.doesNotHaveAllKeys(new Set([{foo: 'bar'}, 'anotherKey'], [{one: 'two'}, 'example']);
               *
               * @name doesNotHaveAllKeys
               * @param {Mixed} object
               * @param {String[]} keys
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.doesNotHaveAllKeys = function (obj, keys, msg) {
                new Assertion(obj, msg, assert.doesNotHaveAllKeys, true).to.not.have.all.keys(keys);
              };
  
              /**
               * ### .hasAnyDeepKeys(object, [keys], [message])
               *
               * Asserts that `object` has at least one of the `keys` provided.
               * Since Sets and Maps can have objects as keys you can use this assertion to perform
               * a deep comparison.
               * You can also provide a single object instead of a `keys` array and its keys
               * will be used as the expected set of keys.
               *
               *     assert.hasAnyDeepKeys(new Map([[{one: 'one'}, 'valueOne'], [1, 2]]), {one: 'one'});
               *     assert.hasAnyDeepKeys(new Map([[{one: 'one'}, 'valueOne'], [1, 2]]), [{one: 'one'}, {two: 'two'}]);
               *     assert.hasAnyDeepKeys(new Map([[{one: 'one'}, 'valueOne'], [{two: 'two'}, 'valueTwo']]), [{one: 'one'}, {two: 'two'}]);
               *     assert.hasAnyDeepKeys(new Set([{one: 'one'}, {two: 'two'}]), {one: 'one'});
               *     assert.hasAnyDeepKeys(new Set([{one: 'one'}, {two: 'two'}]), [{one: 'one'}, {three: 'three'}]);
               *     assert.hasAnyDeepKeys(new Set([{one: 'one'}, {two: 'two'}]), [{one: 'one'}, {two: 'two'}]);
               *
               * @name doesNotHaveAllKeys
               * @param {Mixed} object
               * @param {Array|Object} keys
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.hasAnyDeepKeys = function (obj, keys, msg) {
                new Assertion(obj, msg, assert.hasAnyDeepKeys, true).to.have.any.deep.keys(keys);
              };
  
              /**
               * ### .hasAllDeepKeys(object, [keys], [message])
               *
               * Asserts that `object` has all and only all of the `keys` provided.
               * Since Sets and Maps can have objects as keys you can use this assertion to perform
               * a deep comparison.
               * You can also provide a single object instead of a `keys` array and its keys
               * will be used as the expected set of keys.
               *
               *     assert.hasAllDeepKeys(new Map([[{one: 'one'}, 'valueOne']]), {one: 'one'});
               *     assert.hasAllDeepKeys(new Map([[{one: 'one'}, 'valueOne'], [{two: 'two'}, 'valueTwo']]), [{one: 'one'}, {two: 'two'}]);
               *     assert.hasAllDeepKeys(new Set([{one: 'one'}]), {one: 'one'});
               *     assert.hasAllDeepKeys(new Set([{one: 'one'}, {two: 'two'}]), [{one: 'one'}, {two: 'two'}]);
               *
               * @name hasAllDeepKeys
               * @param {Mixed} object
               * @param {Array|Object} keys
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.hasAllDeepKeys = function (obj, keys, msg) {
                new Assertion(obj, msg, assert.hasAllDeepKeys, true).to.have.all.deep.keys(keys);
              };
  
              /**
               * ### .containsAllDeepKeys(object, [keys], [message])
               *
               * Asserts that `object` contains all of the `keys` provided.
               * Since Sets and Maps can have objects as keys you can use this assertion to perform
               * a deep comparison.
               * You can also provide a single object instead of a `keys` array and its keys
               * will be used as the expected set of keys.
               *
               *     assert.containsAllDeepKeys(new Map([[{one: 'one'}, 'valueOne'], [1, 2]]), {one: 'one'});
               *     assert.containsAllDeepKeys(new Map([[{one: 'one'}, 'valueOne'], [{two: 'two'}, 'valueTwo']]), [{one: 'one'}, {two: 'two'}]);
               *     assert.containsAllDeepKeys(new Set([{one: 'one'}, {two: 'two'}]), {one: 'one'});
               *     assert.containsAllDeepKeys(new Set([{one: 'one'}, {two: 'two'}]), [{one: 'one'}, {two: 'two'}]);
               *
               * @name containsAllDeepKeys
               * @param {Mixed} object
               * @param {Array|Object} keys
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.containsAllDeepKeys = function (obj, keys, msg) {
                new Assertion(obj, msg, assert.containsAllDeepKeys, true).to.contain.all.deep.keys(
                  keys
                );
              };
  
              /**
               * ### .doesNotHaveAnyDeepKeys(object, [keys], [message])
               *
               * Asserts that `object` has none of the `keys` provided.
               * Since Sets and Maps can have objects as keys you can use this assertion to perform
               * a deep comparison.
               * You can also provide a single object instead of a `keys` array and its keys
               * will be used as the expected set of keys.
               *
               *     assert.doesNotHaveAnyDeepKeys(new Map([[{one: 'one'}, 'valueOne'], [1, 2]]), {thisDoesNot: 'exist'});
               *     assert.doesNotHaveAnyDeepKeys(new Map([[{one: 'one'}, 'valueOne'], [{two: 'two'}, 'valueTwo']]), [{twenty: 'twenty'}, {fifty: 'fifty'}]);
               *     assert.doesNotHaveAnyDeepKeys(new Set([{one: 'one'}, {two: 'two'}]), {twenty: 'twenty'});
               *     assert.doesNotHaveAnyDeepKeys(new Set([{one: 'one'}, {two: 'two'}]), [{twenty: 'twenty'}, {fifty: 'fifty'}]);
               *
               * @name doesNotHaveAnyDeepKeys
               * @param {Mixed} object
               * @param {Array|Object} keys
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.doesNotHaveAnyDeepKeys = function (obj, keys, msg) {
                new Assertion(
                  obj,
                  msg,
                  assert.doesNotHaveAnyDeepKeys,
                  true
                ).to.not.have.any.deep.keys(keys);
              };
  
              /**
               * ### .doesNotHaveAllDeepKeys(object, [keys], [message])
               *
               * Asserts that `object` does not have at least one of the `keys` provided.
               * Since Sets and Maps can have objects as keys you can use this assertion to perform
               * a deep comparison.
               * You can also provide a single object instead of a `keys` array and its keys
               * will be used as the expected set of keys.
               *
               *     assert.doesNotHaveAllDeepKeys(new Map([[{one: 'one'}, 'valueOne'], [1, 2]]), {thisDoesNot: 'exist'});
               *     assert.doesNotHaveAllDeepKeys(new Map([[{one: 'one'}, 'valueOne'], [{two: 'two'}, 'valueTwo']]), [{twenty: 'twenty'}, {one: 'one'}]);
               *     assert.doesNotHaveAllDeepKeys(new Set([{one: 'one'}, {two: 'two'}]), {twenty: 'twenty'});
               *     assert.doesNotHaveAllDeepKeys(new Set([{one: 'one'}, {two: 'two'}]), [{one: 'one'}, {fifty: 'fifty'}]);
               *
               * @name doesNotHaveAllDeepKeys
               * @param {Mixed} object
               * @param {Array|Object} keys
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.doesNotHaveAllDeepKeys = function (obj, keys, msg) {
                new Assertion(
                  obj,
                  msg,
                  assert.doesNotHaveAllDeepKeys,
                  true
                ).to.not.have.all.deep.keys(keys);
              };
  
              /**
               * ### .throws(fn, [errorLike/string/regexp], [string/regexp], [message])
               *
               * If `errorLike` is an `Error` constructor, asserts that `fn` will throw an error that is an
               * instance of `errorLike`.
               * If `errorLike` is an `Error` instance, asserts that the error thrown is the same
               * instance as `errorLike`.
               * If `errMsgMatcher` is provided, it also asserts that the error thrown will have a
               * message matching `errMsgMatcher`.
               *
               *     assert.throws(fn, 'Error thrown must have this msg');
               *     assert.throws(fn, /Error thrown must have a msg that matches this/);
               *     assert.throws(fn, ReferenceError);
               *     assert.throws(fn, errorInstance);
               *     assert.throws(fn, ReferenceError, 'Error thrown must be a ReferenceError and have this msg');
               *     assert.throws(fn, errorInstance, 'Error thrown must be the same errorInstance and have this msg');
               *     assert.throws(fn, ReferenceError, /Error thrown must be a ReferenceError and match this/);
               *     assert.throws(fn, errorInstance, /Error thrown must be the same errorInstance and match this/);
               *
               * @name throws
               * @alias throw
               * @alias Throw
               * @param {Function} fn
               * @param {ErrorConstructor|Error} errorLike
               * @param {RegExp|String} errMsgMatcher
               * @param {String} message
               * @see https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Error#Error_types
               * @namespace Assert
               * @api public
               */
  
              assert.throws = function (fn, errorLike, errMsgMatcher, msg) {
                if ('string' === typeof errorLike || errorLike instanceof RegExp) {
                  errMsgMatcher = errorLike;
                  errorLike = null;
                }
  
                var assertErr = new Assertion(fn, msg, assert.throws, true).to.throw(
                  errorLike,
                  errMsgMatcher
                );
                return flag(assertErr, 'object');
              };
  
              /**
               * ### .doesNotThrow(fn, [errorLike/string/regexp], [string/regexp], [message])
               *
               * If `errorLike` is an `Error` constructor, asserts that `fn` will _not_ throw an error that is an
               * instance of `errorLike`.
               * If `errorLike` is an `Error` instance, asserts that the error thrown is _not_ the same
               * instance as `errorLike`.
               * If `errMsgMatcher` is provided, it also asserts that the error thrown will _not_ have a
               * message matching `errMsgMatcher`.
               *
               *     assert.doesNotThrow(fn, 'Any Error thrown must not have this message');
               *     assert.doesNotThrow(fn, /Any Error thrown must not match this/);
               *     assert.doesNotThrow(fn, Error);
               *     assert.doesNotThrow(fn, errorInstance);
               *     assert.doesNotThrow(fn, Error, 'Error must not have this message');
               *     assert.doesNotThrow(fn, errorInstance, 'Error must not have this message');
               *     assert.doesNotThrow(fn, Error, /Error must not match this/);
               *     assert.doesNotThrow(fn, errorInstance, /Error must not match this/);
               *
               * @name doesNotThrow
               * @param {Function} fn
               * @param {ErrorConstructor} errorLike
               * @param {RegExp|String} errMsgMatcher
               * @param {String} message
               * @see https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Error#Error_types
               * @namespace Assert
               * @api public
               */
  
              assert.doesNotThrow = function (fn, errorLike, errMsgMatcher, msg) {
                if ('string' === typeof errorLike || errorLike instanceof RegExp) {
                  errMsgMatcher = errorLike;
                  errorLike = null;
                }
  
                new Assertion(fn, msg, assert.doesNotThrow, true).to.not.throw(
                  errorLike,
                  errMsgMatcher
                );
              };
  
              /**
               * ### .operator(val1, operator, val2, [message])
               *
               * Compares two values using `operator`.
               *
               *     assert.operator(1, '<', 2, 'everything is ok');
               *     assert.operator(1, '>', 2, 'this will fail');
               *
               * @name operator
               * @param {Mixed} val1
               * @param {String} operator
               * @param {Mixed} val2
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.operator = function (val, operator, val2, msg) {
                var ok;
                switch (operator) {
                  case '==':
                    ok = val == val2;
                    break;
                  case '===':
                    ok = val === val2;
                    break;
                  case '>':
                    ok = val > val2;
                    break;
                  case '>=':
                    ok = val >= val2;
                    break;
                  case '<':
                    ok = val < val2;
                    break;
                  case '<=':
                    ok = val <= val2;
                    break;
                  case '!=':
                    ok = val != val2;
                    break;
                  case '!==':
                    ok = val !== val2;
                    break;
                  default:
                    msg = msg ? msg + ': ' : msg;
                    throw new chai.AssertionError(
                      msg + 'Invalid operator "' + operator + '"',
                      undefined,
                      assert.operator
                    );
                }
                var test = new Assertion(ok, msg, assert.operator, true);
                test.assert(
                  true === flag(test, 'object'),
                  'expected ' + util.inspect(val) + ' to be ' + operator + ' ' + util.inspect(val2),
                  'expected ' +
                    util.inspect(val) +
                    ' to not be ' +
                    operator +
                    ' ' +
                    util.inspect(val2)
                );
              };
  
              /**
               * ### .closeTo(actual, expected, delta, [message])
               *
               * Asserts that the target is equal `expected`, to within a +/- `delta` range.
               *
               *     assert.closeTo(1.5, 1, 0.5, 'numbers are close');
               *
               * @name closeTo
               * @param {Number} actual
               * @param {Number} expected
               * @param {Number} delta
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.closeTo = function (act, exp, delta, msg) {
                new Assertion(act, msg, assert.closeTo, true).to.be.closeTo(exp, delta);
              };
  
              /**
               * ### .approximately(actual, expected, delta, [message])
               *
               * Asserts that the target is equal `expected`, to within a +/- `delta` range.
               *
               *     assert.approximately(1.5, 1, 0.5, 'numbers are close');
               *
               * @name approximately
               * @param {Number} actual
               * @param {Number} expected
               * @param {Number} delta
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.approximately = function (act, exp, delta, msg) {
                new Assertion(act, msg, assert.approximately, true).to.be.approximately(exp, delta);
              };
  
              /**
               * ### .sameMembers(set1, set2, [message])
               *
               * Asserts that `set1` and `set2` have the same members in any order. Uses a
               * strict equality check (===).
               *
               *     assert.sameMembers([ 1, 2, 3 ], [ 2, 1, 3 ], 'same members');
               *
               * @name sameMembers
               * @param {Array} set1
               * @param {Array} set2
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.sameMembers = function (set1, set2, msg) {
                new Assertion(set1, msg, assert.sameMembers, true).to.have.same.members(set2);
              };
  
              /**
               * ### .notSameMembers(set1, set2, [message])
               *
               * Asserts that `set1` and `set2` don't have the same members in any order.
               * Uses a strict equality check (===).
               *
               *     assert.notSameMembers([ 1, 2, 3 ], [ 5, 1, 3 ], 'not same members');
               *
               * @name notSameMembers
               * @param {Array} set1
               * @param {Array} set2
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notSameMembers = function (set1, set2, msg) {
                new Assertion(set1, msg, assert.notSameMembers, true).to.not.have.same.members(set2);
              };
  
              /**
               * ### .sameDeepMembers(set1, set2, [message])
               *
               * Asserts that `set1` and `set2` have the same members in any order. Uses a
               * deep equality check.
               *
               *     assert.sameDeepMembers([ { a: 1 }, { b: 2 }, { c: 3 } ], [{ b: 2 }, { a: 1 }, { c: 3 }], 'same deep members');
               *
               * @name sameDeepMembers
               * @param {Array} set1
               * @param {Array} set2
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.sameDeepMembers = function (set1, set2, msg) {
                new Assertion(set1, msg, assert.sameDeepMembers, true).to.have.same.deep.members(
                  set2
                );
              };
  
              /**
               * ### .notSameDeepMembers(set1, set2, [message])
               *
               * Asserts that `set1` and `set2` don't have the same members in any order.
               * Uses a deep equality check.
               *
               *     assert.notSameDeepMembers([ { a: 1 }, { b: 2 }, { c: 3 } ], [{ b: 2 }, { a: 1 }, { f: 5 }], 'not same deep members');
               *
               * @name notSameDeepMembers
               * @param {Array} set1
               * @param {Array} set2
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notSameDeepMembers = function (set1, set2, msg) {
                new Assertion(
                  set1,
                  msg,
                  assert.notSameDeepMembers,
                  true
                ).to.not.have.same.deep.members(set2);
              };
  
              /**
               * ### .sameOrderedMembers(set1, set2, [message])
               *
               * Asserts that `set1` and `set2` have the same members in the same order.
               * Uses a strict equality check (===).
               *
               *     assert.sameOrderedMembers([ 1, 2, 3 ], [ 1, 2, 3 ], 'same ordered members');
               *
               * @name sameOrderedMembers
               * @param {Array} set1
               * @param {Array} set2
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.sameOrderedMembers = function (set1, set2, msg) {
                new Assertion(
                  set1,
                  msg,
                  assert.sameOrderedMembers,
                  true
                ).to.have.same.ordered.members(set2);
              };
  
              /**
               * ### .notSameOrderedMembers(set1, set2, [message])
               *
               * Asserts that `set1` and `set2` don't have the same members in the same
               * order. Uses a strict equality check (===).
               *
               *     assert.notSameOrderedMembers([ 1, 2, 3 ], [ 2, 1, 3 ], 'not same ordered members');
               *
               * @name notSameOrderedMembers
               * @param {Array} set1
               * @param {Array} set2
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notSameOrderedMembers = function (set1, set2, msg) {
                new Assertion(
                  set1,
                  msg,
                  assert.notSameOrderedMembers,
                  true
                ).to.not.have.same.ordered.members(set2);
              };
  
              /**
               * ### .sameDeepOrderedMembers(set1, set2, [message])
               *
               * Asserts that `set1` and `set2` have the same members in the same order.
               * Uses a deep equality check.
               *
               * assert.sameDeepOrderedMembers([ { a: 1 }, { b: 2 }, { c: 3 } ], [ { a: 1 }, { b: 2 }, { c: 3 } ], 'same deep ordered members');
               *
               * @name sameDeepOrderedMembers
               * @param {Array} set1
               * @param {Array} set2
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.sameDeepOrderedMembers = function (set1, set2, msg) {
                new Assertion(
                  set1,
                  msg,
                  assert.sameDeepOrderedMembers,
                  true
                ).to.have.same.deep.ordered.members(set2);
              };
  
              /**
               * ### .notSameDeepOrderedMembers(set1, set2, [message])
               *
               * Asserts that `set1` and `set2` don't have the same members in the same
               * order. Uses a deep equality check.
               *
               * assert.notSameDeepOrderedMembers([ { a: 1 }, { b: 2 }, { c: 3 } ], [ { a: 1 }, { b: 2 }, { z: 5 } ], 'not same deep ordered members');
               * assert.notSameDeepOrderedMembers([ { a: 1 }, { b: 2 }, { c: 3 } ], [ { b: 2 }, { a: 1 }, { c: 3 } ], 'not same deep ordered members');
               *
               * @name notSameDeepOrderedMembers
               * @param {Array} set1
               * @param {Array} set2
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notSameDeepOrderedMembers = function (set1, set2, msg) {
                new Assertion(
                  set1,
                  msg,
                  assert.notSameDeepOrderedMembers,
                  true
                ).to.not.have.same.deep.ordered.members(set2);
              };
  
              /**
               * ### .includeMembers(superset, subset, [message])
               *
               * Asserts that `subset` is included in `superset` in any order. Uses a
               * strict equality check (===). Duplicates are ignored.
               *
               *     assert.includeMembers([ 1, 2, 3 ], [ 2, 1, 2 ], 'include members');
               *
               * @name includeMembers
               * @param {Array} superset
               * @param {Array} subset
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.includeMembers = function (superset, subset, msg) {
                new Assertion(superset, msg, assert.includeMembers, true).to.include.members(subset);
              };
  
              /**
               * ### .notIncludeMembers(superset, subset, [message])
               *
               * Asserts that `subset` isn't included in `superset` in any order. Uses a
               * strict equality check (===). Duplicates are ignored.
               *
               *     assert.notIncludeMembers([ 1, 2, 3 ], [ 5, 1 ], 'not include members');
               *
               * @name notIncludeMembers
               * @param {Array} superset
               * @param {Array} subset
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notIncludeMembers = function (superset, subset, msg) {
                new Assertion(superset, msg, assert.notIncludeMembers, true).to.not.include.members(
                  subset
                );
              };
  
              /**
               * ### .includeDeepMembers(superset, subset, [message])
               *
               * Asserts that `subset` is included in `superset` in any order. Uses a deep
               * equality check. Duplicates are ignored.
               *
               *     assert.includeDeepMembers([ { a: 1 }, { b: 2 }, { c: 3 } ], [ { b: 2 }, { a: 1 }, { b: 2 } ], 'include deep members');
               *
               * @name includeDeepMembers
               * @param {Array} superset
               * @param {Array} subset
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.includeDeepMembers = function (superset, subset, msg) {
                new Assertion(superset, msg, assert.includeDeepMembers, true).to.include.deep.members(
                  subset
                );
              };
  
              /**
               * ### .notIncludeDeepMembers(superset, subset, [message])
               *
               * Asserts that `subset` isn't included in `superset` in any order. Uses a
               * deep equality check. Duplicates are ignored.
               *
               *     assert.notIncludeDeepMembers([ { a: 1 }, { b: 2 }, { c: 3 } ], [ { b: 2 }, { f: 5 } ], 'not include deep members');
               *
               * @name notIncludeDeepMembers
               * @param {Array} superset
               * @param {Array} subset
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notIncludeDeepMembers = function (superset, subset, msg) {
                new Assertion(
                  superset,
                  msg,
                  assert.notIncludeDeepMembers,
                  true
                ).to.not.include.deep.members(subset);
              };
  
              /**
               * ### .includeOrderedMembers(superset, subset, [message])
               *
               * Asserts that `subset` is included in `superset` in the same order
               * beginning with the first element in `superset`. Uses a strict equality
               * check (===).
               *
               *     assert.includeOrderedMembers([ 1, 2, 3 ], [ 1, 2 ], 'include ordered members');
               *
               * @name includeOrderedMembers
               * @param {Array} superset
               * @param {Array} subset
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.includeOrderedMembers = function (superset, subset, msg) {
                new Assertion(
                  superset,
                  msg,
                  assert.includeOrderedMembers,
                  true
                ).to.include.ordered.members(subset);
              };
  
              /**
               * ### .notIncludeOrderedMembers(superset, subset, [message])
               *
               * Asserts that `subset` isn't included in `superset` in the same order
               * beginning with the first element in `superset`. Uses a strict equality
               * check (===).
               *
               *     assert.notIncludeOrderedMembers([ 1, 2, 3 ], [ 2, 1 ], 'not include ordered members');
               *     assert.notIncludeOrderedMembers([ 1, 2, 3 ], [ 2, 3 ], 'not include ordered members');
               *
               * @name notIncludeOrderedMembers
               * @param {Array} superset
               * @param {Array} subset
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notIncludeOrderedMembers = function (superset, subset, msg) {
                new Assertion(
                  superset,
                  msg,
                  assert.notIncludeOrderedMembers,
                  true
                ).to.not.include.ordered.members(subset);
              };
  
              /**
               * ### .includeDeepOrderedMembers(superset, subset, [message])
               *
               * Asserts that `subset` is included in `superset` in the same order
               * beginning with the first element in `superset`. Uses a deep equality
               * check.
               *
               *     assert.includeDeepOrderedMembers([ { a: 1 }, { b: 2 }, { c: 3 } ], [ { a: 1 }, { b: 2 } ], 'include deep ordered members');
               *
               * @name includeDeepOrderedMembers
               * @param {Array} superset
               * @param {Array} subset
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.includeDeepOrderedMembers = function (superset, subset, msg) {
                new Assertion(
                  superset,
                  msg,
                  assert.includeDeepOrderedMembers,
                  true
                ).to.include.deep.ordered.members(subset);
              };
  
              /**
               * ### .notIncludeDeepOrderedMembers(superset, subset, [message])
               *
               * Asserts that `subset` isn't included in `superset` in the same order
               * beginning with the first element in `superset`. Uses a deep equality
               * check.
               *
               *     assert.notIncludeDeepOrderedMembers([ { a: 1 }, { b: 2 }, { c: 3 } ], [ { a: 1 }, { f: 5 } ], 'not include deep ordered members');
               *     assert.notIncludeDeepOrderedMembers([ { a: 1 }, { b: 2 }, { c: 3 } ], [ { b: 2 }, { a: 1 } ], 'not include deep ordered members');
               *     assert.notIncludeDeepOrderedMembers([ { a: 1 }, { b: 2 }, { c: 3 } ], [ { b: 2 }, { c: 3 } ], 'not include deep ordered members');
               *
               * @name notIncludeDeepOrderedMembers
               * @param {Array} superset
               * @param {Array} subset
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.notIncludeDeepOrderedMembers = function (superset, subset, msg) {
                new Assertion(
                  superset,
                  msg,
                  assert.notIncludeDeepOrderedMembers,
                  true
                ).to.not.include.deep.ordered.members(subset);
              };
  
              /**
               * ### .oneOf(inList, list, [message])
               *
               * Asserts that non-object, non-array value `inList` appears in the flat array `list`.
               *
               *     assert.oneOf(1, [ 2, 1 ], 'Not found in list');
               *
               * @name oneOf
               * @param {*} inList
               * @param {Array<*>} list
               * @param {String} message
               * @namespace Assert
               * @api public
               */
  
              assert.oneOf = function (inList, list, msg) {
                new Assertion(inList, msg, assert.oneOf, true).to.be.oneOf(list);
              };
  
              /**
               * ### .changes(function, object, property, [message])
               *
               * Asserts that a function changes the value of a property.
               *
               *     var obj = { val: 10 };
               *     var fn = function() { obj.val = 22 };
               *     assert.changes(fn, obj, 'val');
               *
               * @name changes
               * @param {Function} modifier function
               * @param {Object} object or getter function
               * @param {String} property name _optional_
               * @param {String} message _optional_
               * @namespace Assert
               * @api public
               */
  
              assert.changes = function (fn, obj, prop, msg) {
                if (arguments.length === 3 && typeof obj === 'function') {
                  msg = prop;
                  prop = null;
                }
  
                new Assertion(fn, msg, assert.changes, true).to.change(obj, prop);
              };
  
              /**
               * ### .changesBy(function, object, property, delta, [message])
               *
               * Asserts that a function changes the value of a property by an amount (delta).
               *
               *     var obj = { val: 10 };
               *     var fn = function() { obj.val += 2 };
               *     assert.changesBy(fn, obj, 'val', 2);
               *
               * @name changesBy
               * @param {Function} modifier function
               * @param {Object} object or getter function
               * @param {String} property name _optional_
               * @param {Number} change amount (delta)
               * @param {String} message _optional_
               * @namespace Assert
               * @api public
               */
  
              assert.changesBy = function (fn, obj, prop, delta, msg) {
                if (arguments.length === 4 && typeof obj === 'function') {
                  var tmpMsg = delta;
                  delta = prop;
                  msg = tmpMsg;
                } else if (arguments.length === 3) {
                  delta = prop;
                  prop = null;
                }
  
                new Assertion(fn, msg, assert.changesBy, true).to.change(obj, prop).by(delta);
              };
  
              /**
               * ### .doesNotChange(function, object, property, [message])
               *
               * Asserts that a function does not change the value of a property.
               *
               *     var obj = { val: 10 };
               *     var fn = function() { console.log('foo'); };
               *     assert.doesNotChange(fn, obj, 'val');
               *
               * @name doesNotChange
               * @param {Function} modifier function
               * @param {Object} object or getter function
               * @param {String} property name _optional_
               * @param {String} message _optional_
               * @namespace Assert
               * @api public
               */
  
              assert.doesNotChange = function (fn, obj, prop, msg) {
                if (arguments.length === 3 && typeof obj === 'function') {
                  msg = prop;
                  prop = null;
                }
  
                return new Assertion(fn, msg, assert.doesNotChange, true).to.not.change(obj, prop);
              };
  
              /**
               * ### .changesButNotBy(function, object, property, delta, [message])
               *
               * Asserts that a function does not change the value of a property or of a function's return value by an amount (delta)
               *
               *     var obj = { val: 10 };
               *     var fn = function() { obj.val += 10 };
               *     assert.changesButNotBy(fn, obj, 'val', 5);
               *
               * @name changesButNotBy
               * @param {Function} modifier function
               * @param {Object} object or getter function
               * @param {String} property name _optional_
               * @param {Number} change amount (delta)
               * @param {String} message _optional_
               * @namespace Assert
               * @api public
               */
  
              assert.changesButNotBy = function (fn, obj, prop, delta, msg) {
                if (arguments.length === 4 && typeof obj === 'function') {
                  var tmpMsg = delta;
                  delta = prop;
                  msg = tmpMsg;
                } else if (arguments.length === 3) {
                  delta = prop;
                  prop = null;
                }
  
                new Assertion(fn, msg, assert.changesButNotBy, true).to
                  .change(obj, prop)
                  .but.not.by(delta);
              };
  
              /**
               * ### .increases(function, object, property, [message])
               *
               * Asserts that a function increases a numeric object property.
               *
               *     var obj = { val: 10 };
               *     var fn = function() { obj.val = 13 };
               *     assert.increases(fn, obj, 'val');
               *
               * @name increases
               * @param {Function} modifier function
               * @param {Object} object or getter function
               * @param {String} property name _optional_
               * @param {String} message _optional_
               * @namespace Assert
               * @api public
               */
  
              assert.increases = function (fn, obj, prop, msg) {
                if (arguments.length === 3 && typeof obj === 'function') {
                  msg = prop;
                  prop = null;
                }
  
                return new Assertion(fn, msg, assert.increases, true).to.increase(obj, prop);
              };
  
              /**
               * ### .increasesBy(function, object, property, delta, [message])
               *
               * Asserts that a function increases a numeric object property or a function's return value by an amount (delta).
               *
               *     var obj = { val: 10 };
               *     var fn = function() { obj.val += 10 };
               *     assert.increasesBy(fn, obj, 'val', 10);
               *
               * @name increasesBy
               * @param {Function} modifier function
               * @param {Object} object or getter function
               * @param {String} property name _optional_
               * @param {Number} change amount (delta)
               * @param {String} message _optional_
               * @namespace Assert
               * @api public
               */
  
              assert.increasesBy = function (fn, obj, prop, delta, msg) {
                if (arguments.length === 4 && typeof obj === 'function') {
                  var tmpMsg = delta;
                  delta = prop;
                  msg = tmpMsg;
                } else if (arguments.length === 3) {
                  delta = prop;
                  prop = null;
                }
  
                new Assertion(fn, msg, assert.increasesBy, true).to.increase(obj, prop).by(delta);
              };
  
              /**
               * ### .doesNotIncrease(function, object, property, [message])
               *
               * Asserts that a function does not increase a numeric object property.
               *
               *     var obj = { val: 10 };
               *     var fn = function() { obj.val = 8 };
               *     assert.doesNotIncrease(fn, obj, 'val');
               *
               * @name doesNotIncrease
               * @param {Function} modifier function
               * @param {Object} object or getter function
               * @param {String} property name _optional_
               * @param {String} message _optional_
               * @namespace Assert
               * @api public
               */
  
              assert.doesNotIncrease = function (fn, obj, prop, msg) {
                if (arguments.length === 3 && typeof obj === 'function') {
                  msg = prop;
                  prop = null;
                }
  
                return new Assertion(fn, msg, assert.doesNotIncrease, true).to.not.increase(
                  obj,
                  prop
                );
              };
  
              /**
               * ### .increasesButNotBy(function, object, property, [message])
               *
               * Asserts that a function does not increase a numeric object property or function's return value by an amount (delta).
               *
               *     var obj = { val: 10 };
               *     var fn = function() { obj.val = 15 };
               *     assert.increasesButNotBy(fn, obj, 'val', 10);
               *
               * @name increasesButNotBy
               * @param {Function} modifier function
               * @param {Object} object or getter function
               * @param {String} property name _optional_
               * @param {Number} change amount (delta)
               * @param {String} message _optional_
               * @namespace Assert
               * @api public
               */
  
              assert.increasesButNotBy = function (fn, obj, prop, delta, msg) {
                if (arguments.length === 4 && typeof obj === 'function') {
                  var tmpMsg = delta;
                  delta = prop;
                  msg = tmpMsg;
                } else if (arguments.length === 3) {
                  delta = prop;
                  prop = null;
                }
  
                new Assertion(fn, msg, assert.increasesButNotBy, true).to
                  .increase(obj, prop)
                  .but.not.by(delta);
              };
  
              /**
               * ### .decreases(function, object, property, [message])
               *
               * Asserts that a function decreases a numeric object property.
               *
               *     var obj = { val: 10 };
               *     var fn = function() { obj.val = 5 };
               *     assert.decreases(fn, obj, 'val');
               *
               * @name decreases
               * @param {Function} modifier function
               * @param {Object} object or getter function
               * @param {String} property name _optional_
               * @param {String} message _optional_
               * @namespace Assert
               * @api public
               */
  
              assert.decreases = function (fn, obj, prop, msg) {
                if (arguments.length === 3 && typeof obj === 'function') {
                  msg = prop;
                  prop = null;
                }
  
                return new Assertion(fn, msg, assert.decreases, true).to.decrease(obj, prop);
              };
  
              /**
               * ### .decreasesBy(function, object, property, delta, [message])
               *
               * Asserts that a function decreases a numeric object property or a function's return value by an amount (delta)
               *
               *     var obj = { val: 10 };
               *     var fn = function() { obj.val -= 5 };
               *     assert.decreasesBy(fn, obj, 'val', 5);
               *
               * @name decreasesBy
               * @param {Function} modifier function
               * @param {Object} object or getter function
               * @param {String} property name _optional_
               * @param {Number} change amount (delta)
               * @param {String} message _optional_
               * @namespace Assert
               * @api public
               */
  
              assert.decreasesBy = function (fn, obj, prop, delta, msg) {
                if (arguments.length === 4 && typeof obj === 'function') {
                  var tmpMsg = delta;
                  delta = prop;
                  msg = tmpMsg;
                } else if (arguments.length === 3) {
                  delta = prop;
                  prop = null;
                }
  
                new Assertion(fn, msg, assert.decreasesBy, true).to.decrease(obj, prop).by(delta);
              };
  
              /**
               * ### .doesNotDecrease(function, object, property, [message])
               *
               * Asserts that a function does not decreases a numeric object property.
               *
               *     var obj = { val: 10 };
               *     var fn = function() { obj.val = 15 };
               *     assert.doesNotDecrease(fn, obj, 'val');
               *
               * @name doesNotDecrease
               * @param {Function} modifier function
               * @param {Object} object or getter function
               * @param {String} property name _optional_
               * @param {String} message _optional_
               * @namespace Assert
               * @api public
               */
  
              assert.doesNotDecrease = function (fn, obj, prop, msg) {
                if (arguments.length === 3 && typeof obj === 'function') {
                  msg = prop;
                  prop = null;
                }
  
                return new Assertion(fn, msg, assert.doesNotDecrease, true).to.not.decrease(
                  obj,
                  prop
                );
              };
  
              /**
               * ### .doesNotDecreaseBy(function, object, property, delta, [message])
               *
               * Asserts that a function does not decreases a numeric object property or a function's return value by an amount (delta)
               *
               *     var obj = { val: 10 };
               *     var fn = function() { obj.val = 5 };
               *     assert.doesNotDecreaseBy(fn, obj, 'val', 1);
               *
               * @name doesNotDecrease
               * @param {Function} modifier function
               * @param {Object} object or getter function
               * @param {String} property name _optional_
               * @param {Number} change amount (delta)
               * @param {String} message _optional_
               * @namespace Assert
               * @api public
               */
  
              assert.doesNotDecreaseBy = function (fn, obj, prop, delta, msg) {
                if (arguments.length === 4 && typeof obj === 'function') {
                  var tmpMsg = delta;
                  delta = prop;
                  msg = tmpMsg;
                } else if (arguments.length === 3) {
                  delta = prop;
                  prop = null;
                }
  
                return new Assertion(fn, msg, assert.doesNotDecreaseBy, true).to.not
                  .decrease(obj, prop)
                  .by(delta);
              };
  
              /**
               * ### .decreasesButNotBy(function, object, property, delta, [message])
               *
               * Asserts that a function does not decreases a numeric object property or a function's return value by an amount (delta)
               *
               *     var obj = { val: 10 };
               *     var fn = function() { obj.val = 5 };
               *     assert.decreasesButNotBy(fn, obj, 'val', 1);
               *
               * @name decreasesButNotBy
               * @param {Function} modifier function
               * @param {Object} object or getter function
               * @param {String} property name _optional_
               * @param {Number} change amount (delta)
               * @param {String} message _optional_
               * @namespace Assert
               * @api public
               */
  
              assert.decreasesButNotBy = function (fn, obj, prop, delta, msg) {
                if (arguments.length === 4 && typeof obj === 'function') {
                  var tmpMsg = delta;
                  delta = prop;
                  msg = tmpMsg;
                } else if (arguments.length === 3) {
                  delta = prop;
                  prop = null;
                }
  
                new Assertion(fn, msg, assert.decreasesButNotBy, true).to
                  .decrease(obj, prop)
                  .but.not.by(delta);
              };
  
              /*!
               * ### .ifError(object)
               *
               * Asserts if value is not a false value, and throws if it is a true value.
               * This is added to allow for chai to be a drop-in replacement for Node's
               * assert class.
               *
               *     var err = new Error('I am a custom error');
               *     assert.ifError(err); // Rethrows err!
               *
               * @name ifError
               * @param {Object} object
               * @namespace Assert
               * @api public
               */
  
              assert.ifError = function (val) {
                if (val) {
                  throw val;
                }
              };
  
              /**
               * ### .isExtensible(object)
               *
               * Asserts that `object` is extensible (can have new properties added to it).
               *
               *     assert.isExtensible({});
               *
               * @name isExtensible
               * @alias extensible
               * @param {Object} object
               * @param {String} message _optional_
               * @namespace Assert
               * @api public
               */
  
              assert.isExtensible = function (obj, msg) {
                new Assertion(obj, msg, assert.isExtensible, true).to.be.extensible;
              };
  
              /**
               * ### .isNotExtensible(object)
               *
               * Asserts that `object` is _not_ extensible.
               *
               *     var nonExtensibleObject = Object.preventExtensions({});
               *     var sealedObject = Object.seal({});
               *     var frozenObject = Object.freeze({});
               *
               *     assert.isNotExtensible(nonExtensibleObject);
               *     assert.isNotExtensible(sealedObject);
               *     assert.isNotExtensible(frozenObject);
               *
               * @name isNotExtensible
               * @alias notExtensible
               * @param {Object} object
               * @param {String} message _optional_
               * @namespace Assert
               * @api public
               */
  
              assert.isNotExtensible = function (obj, msg) {
                new Assertion(obj, msg, assert.isNotExtensible, true).to.not.be.extensible;
              };
  
              /**
               * ### .isSealed(object)
               *
               * Asserts that `object` is sealed (cannot have new properties added to it
               * and its existing properties cannot be removed).
               *
               *     var sealedObject = Object.seal({});
               *     var frozenObject = Object.seal({});
               *
               *     assert.isSealed(sealedObject);
               *     assert.isSealed(frozenObject);
               *
               * @name isSealed
               * @alias sealed
               * @param {Object} object
               * @param {String} message _optional_
               * @namespace Assert
               * @api public
               */
  
              assert.isSealed = function (obj, msg) {
                new Assertion(obj, msg, assert.isSealed, true).to.be.sealed;
              };
  
              /**
               * ### .isNotSealed(object)
               *
               * Asserts that `object` is _not_ sealed.
               *
               *     assert.isNotSealed({});
               *
               * @name isNotSealed
               * @alias notSealed
               * @param {Object} object
               * @param {String} message _optional_
               * @namespace Assert
               * @api public
               */
  
              assert.isNotSealed = function (obj, msg) {
                new Assertion(obj, msg, assert.isNotSealed, true).to.not.be.sealed;
              };
  
              /**
               * ### .isFrozen(object)
               *
               * Asserts that `object` is frozen (cannot have new properties added to it
               * and its existing properties cannot be modified).
               *
               *     var frozenObject = Object.freeze({});
               *     assert.frozen(frozenObject);
               *
               * @name isFrozen
               * @alias frozen
               * @param {Object} object
               * @param {String} message _optional_
               * @namespace Assert
               * @api public
               */
  
              assert.isFrozen = function (obj, msg) {
                new Assertion(obj, msg, assert.isFrozen, true).to.be.frozen;
              };
  
              /**
               * ### .isNotFrozen(object)
               *
               * Asserts that `object` is _not_ frozen.
               *
               *     assert.isNotFrozen({});
               *
               * @name isNotFrozen
               * @alias notFrozen
               * @param {Object} object
               * @param {String} message _optional_
               * @namespace Assert
               * @api public
               */
  
              assert.isNotFrozen = function (obj, msg) {
                new Assertion(obj, msg, assert.isNotFrozen, true).to.not.be.frozen;
              };
  
              /**
               * ### .isEmpty(target)
               *
               * Asserts that the target does not contain any values.
               * For arrays and strings, it checks the `length` property.
               * For `Map` and `Set` instances, it checks the `size` property.
               * For non-function objects, it gets the count of own
               * enumerable string keys.
               *
               *     assert.isEmpty([]);
               *     assert.isEmpty('');
               *     assert.isEmpty(new Map);
               *     assert.isEmpty({});
               *
               * @name isEmpty
               * @alias empty
               * @param {Object|Array|String|Map|Set} target
               * @param {String} message _optional_
               * @namespace Assert
               * @api public
               */
  
              assert.isEmpty = function (val, msg) {
                new Assertion(val, msg, assert.isEmpty, true).to.be.empty;
              };
  
              /**
               * ### .isNotEmpty(target)
               *
               * Asserts that the target contains values.
               * For arrays and strings, it checks the `length` property.
               * For `Map` and `Set` instances, it checks the `size` property.
               * For non-function objects, it gets the count of own
               * enumerable string keys.
               *
               *     assert.isNotEmpty([1, 2]);
               *     assert.isNotEmpty('34');
               *     assert.isNotEmpty(new Set([5, 6]));
               *     assert.isNotEmpty({ key: 7 });
               *
               * @name isNotEmpty
               * @alias notEmpty
               * @param {Object|Array|String|Map|Set} target
               * @param {String} message _optional_
               * @namespace Assert
               * @api public
               */
  
              assert.isNotEmpty = function (val, msg) {
                new Assertion(val, msg, assert.isNotEmpty, true).to.not.be.empty;
              };
  
              /*!
               * Aliases.
               */
  
              (function alias(name, as) {
                assert[as] = assert[name];
                return alias;
              })('isOk', 'ok')('isNotOk', 'notOk')('throws', 'throw')('throws', 'Throw')(
                'isExtensible',
                'extensible'
              )('isNotExtensible', 'notExtensible')('isSealed', 'sealed')('isNotSealed', 'notSealed')(
                'isFrozen',
                'frozen'
              )('isNotFrozen', 'notFrozen')('isEmpty', 'empty')('isNotEmpty', 'notEmpty');
            };
          },
          {},
        ],
        7: [
          function (require, module, exports) {
            /*!
             * chai
             * Copyright(c) 2011-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            module.exports = function (chai, util) {
              chai.expect = function (val, message) {
                return new chai.Assertion(val, message);
              };
  
              /**
               * ### .fail([message])
               * ### .fail(actual, expected, [message], [operator])
               *
               * Throw a failure.
               *
               *     expect.fail();
               *     expect.fail("custom error message");
               *     expect.fail(1, 2);
               *     expect.fail(1, 2, "custom error message");
               *     expect.fail(1, 2, "custom error message", ">");
               *     expect.fail(1, 2, undefined, ">");
               *
               * @name fail
               * @param {Mixed} actual
               * @param {Mixed} expected
               * @param {String} message
               * @param {String} operator
               * @namespace BDD
               * @api public
               */
  
              chai.expect.fail = function (actual, expected, message, operator) {
                if (arguments.length < 2) {
                  message = actual;
                  actual = undefined;
                }
  
                message = message || 'expect.fail()';
                throw new chai.AssertionError(
                  message,
                  {
                    actual: actual,
                    expected: expected,
                    operator: operator,
                  },
                  chai.expect.fail
                );
              };
            };
          },
          {},
        ],
        8: [
          function (require, module, exports) {
            /*!
             * chai
             * Copyright(c) 2011-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            module.exports = function (chai, util) {
              var Assertion = chai.Assertion;
  
              function loadShould() {
                // explicitly define this method as function as to have it's name to include as `ssfi`
                function shouldGetter() {
                  if (
                    this instanceof String ||
                    this instanceof Number ||
                    this instanceof Boolean ||
                    (typeof Symbol === 'function' && this instanceof Symbol)
                  ) {
                    return new Assertion(this.valueOf(), null, shouldGetter);
                  }
                  return new Assertion(this, null, shouldGetter);
                }
                function shouldSetter(value) {
                  // See https://github.com/chaijs/chai/issues/86: this makes
                  // `whatever.should = someValue` actually set `someValue`, which is
                  // especially useful for `global.should = require('chai').should()`.
                  //
                  // Note that we have to use [[DefineProperty]] instead of [[Put]]
                  // since otherwise we would trigger this very setter!
                  Object.defineProperty(this, 'should', {
                    value: value,
                    enumerable: true,
                    configurable: true,
                    writable: true,
                  });
                }
                // modify Object.prototype to have `should`
                Object.defineProperty(Object.prototype, 'should', {
                  set: shouldSetter,
                  get: shouldGetter,
                  configurable: true,
                });
  
                var should = {};
  
                /**
                 * ### .fail([message])
                 * ### .fail(actual, expected, [message], [operator])
                 *
                 * Throw a failure.
                 *
                 *     should.fail();
                 *     should.fail("custom error message");
                 *     should.fail(1, 2);
                 *     should.fail(1, 2, "custom error message");
                 *     should.fail(1, 2, "custom error message", ">");
                 *     should.fail(1, 2, undefined, ">");
                 *
                 *
                 * @name fail
                 * @param {Mixed} actual
                 * @param {Mixed} expected
                 * @param {String} message
                 * @param {String} operator
                 * @namespace BDD
                 * @api public
                 */
  
                should.fail = function (actual, expected, message, operator) {
                  if (arguments.length < 2) {
                    message = actual;
                    actual = undefined;
                  }
  
                  message = message || 'should.fail()';
                  throw new chai.AssertionError(
                    message,
                    {
                      actual: actual,
                      expected: expected,
                      operator: operator,
                    },
                    should.fail
                  );
                };
  
                /**
                 * ### .equal(actual, expected, [message])
                 *
                 * Asserts non-strict equality (`==`) of `actual` and `expected`.
                 *
                 *     should.equal(3, '3', '== coerces values to strings');
                 *
                 * @name equal
                 * @param {Mixed} actual
                 * @param {Mixed} expected
                 * @param {String} message
                 * @namespace Should
                 * @api public
                 */
  
                should.equal = function (val1, val2, msg) {
                  new Assertion(val1, msg).to.equal(val2);
                };
  
                /**
                 * ### .throw(function, [constructor/string/regexp], [string/regexp], [message])
                 *
                 * Asserts that `function` will throw an error that is an instance of
                 * `constructor`, or alternately that it will throw an error with message
                 * matching `regexp`.
                 *
                 *     should.throw(fn, 'function throws a reference error');
                 *     should.throw(fn, /function throws a reference error/);
                 *     should.throw(fn, ReferenceError);
                 *     should.throw(fn, ReferenceError, 'function throws a reference error');
                 *     should.throw(fn, ReferenceError, /function throws a reference error/);
                 *
                 * @name throw
                 * @alias Throw
                 * @param {Function} function
                 * @param {ErrorConstructor} constructor
                 * @param {RegExp} regexp
                 * @param {String} message
                 * @see https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Error#Error_types
                 * @namespace Should
                 * @api public
                 */
  
                should.Throw = function (fn, errt, errs, msg) {
                  new Assertion(fn, msg).to.Throw(errt, errs);
                };
  
                /**
                 * ### .exist
                 *
                 * Asserts that the target is neither `null` nor `undefined`.
                 *
                 *     var foo = 'hi';
                 *
                 *     should.exist(foo, 'foo exists');
                 *
                 * @name exist
                 * @namespace Should
                 * @api public
                 */
  
                should.exist = function (val, msg) {
                  new Assertion(val, msg).to.exist;
                };
  
                // negation
                should.not = {};
  
                /**
                 * ### .not.equal(actual, expected, [message])
                 *
                 * Asserts non-strict inequality (`!=`) of `actual` and `expected`.
                 *
                 *     should.not.equal(3, 4, 'these numbers are not equal');
                 *
                 * @name not.equal
                 * @param {Mixed} actual
                 * @param {Mixed} expected
                 * @param {String} message
                 * @namespace Should
                 * @api public
                 */
  
                should.not.equal = function (val1, val2, msg) {
                  new Assertion(val1, msg).to.not.equal(val2);
                };
  
                /**
                 * ### .throw(function, [constructor/regexp], [message])
                 *
                 * Asserts that `function` will _not_ throw an error that is an instance of
                 * `constructor`, or alternately that it will not throw an error with message
                 * matching `regexp`.
                 *
                 *     should.not.throw(fn, Error, 'function does not throw');
                 *
                 * @name not.throw
                 * @alias not.Throw
                 * @param {Function} function
                 * @param {ErrorConstructor} constructor
                 * @param {RegExp} regexp
                 * @param {String} message
                 * @see https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Error#Error_types
                 * @namespace Should
                 * @api public
                 */
  
                should.not.Throw = function (fn, errt, errs, msg) {
                  new Assertion(fn, msg).to.not.Throw(errt, errs);
                };
  
                /**
                 * ### .not.exist
                 *
                 * Asserts that the target is neither `null` nor `undefined`.
                 *
                 *     var bar = null;
                 *
                 *     should.not.exist(bar, 'bar does not exist');
                 *
                 * @name not.exist
                 * @namespace Should
                 * @api public
                 */
  
                should.not.exist = function (val, msg) {
                  new Assertion(val, msg).to.not.exist;
                };
  
                should['throw'] = should['Throw'];
                should.not['throw'] = should.not['Throw'];
  
                return should;
              }
  
              chai.should = loadShould;
              chai.Should = loadShould;
            };
          },
          {},
        ],
        9: [
          function (require, module, exports) {
            /*!
             * Chai - addChainingMethod utility
             * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            /*!
             * Module dependencies
             */
  
            var addLengthGuard = require('./addLengthGuard');
            var chai = require('../../chai');
            var flag = require('./flag');
            var proxify = require('./proxify');
            var transferFlags = require('./transferFlags');
  
            /*!
             * Module variables
             */
  
            // Check whether `Object.setPrototypeOf` is supported
            var canSetPrototype = typeof Object.setPrototypeOf === 'function';
  
            // Without `Object.setPrototypeOf` support, this module will need to add properties to a function.
            // However, some of functions' own props are not configurable and should be skipped.
            var testFn = function () {};
            var excludeNames = Object.getOwnPropertyNames(testFn).filter(function (name) {
              var propDesc = Object.getOwnPropertyDescriptor(testFn, name);
  
              // Note: PhantomJS 1.x includes `callee` as one of `testFn`'s own properties,
              // but then returns `undefined` as the property descriptor for `callee`. As a
              // workaround, we perform an otherwise unnecessary type-check for `propDesc`,
              // and then filter it out if it's not an object as it should be.
              if (typeof propDesc !== 'object') return true;
  
              return !propDesc.configurable;
            });
  
            // Cache `Function` properties
            var call = Function.prototype.call,
              apply = Function.prototype.apply;
  
            /**
             * ### .addChainableMethod(ctx, name, method, chainingBehavior)
             *
             * Adds a method to an object, such that the method can also be chained.
             *
             *     utils.addChainableMethod(chai.Assertion.prototype, 'foo', function (str) {
             *       var obj = utils.flag(this, 'object');
             *       new chai.Assertion(obj).to.be.equal(str);
             *     });
             *
             * Can also be accessed directly from `chai.Assertion`.
             *
             *     chai.Assertion.addChainableMethod('foo', fn, chainingBehavior);
             *
             * The result can then be used as both a method assertion, executing both `method` and
             * `chainingBehavior`, or as a language chain, which only executes `chainingBehavior`.
             *
             *     expect(fooStr).to.be.foo('bar');
             *     expect(fooStr).to.be.foo.equal('foo');
             *
             * @param {Object} ctx object to which the method is added
             * @param {String} name of method to add
             * @param {Function} method function to be used for `name`, when called
             * @param {Function} chainingBehavior function to be called every time the property is accessed
             * @namespace Utils
             * @name addChainableMethod
             * @api public
             */
  
            module.exports = function addChainableMethod(ctx, name, method, chainingBehavior) {
              if (typeof chainingBehavior !== 'function') {
                chainingBehavior = function () {};
              }
  
              var chainableBehavior = {
                method: method,
                chainingBehavior: chainingBehavior,
              };
  
              // save the methods so we can overwrite them later, if we need to.
              if (!ctx.__methods) {
                ctx.__methods = {};
              }
              ctx.__methods[name] = chainableBehavior;
  
              Object.defineProperty(ctx, name, {
                get: function chainableMethodGetter() {
                  chainableBehavior.chainingBehavior.call(this);
  
                  var chainableMethodWrapper = function () {
                    // Setting the `ssfi` flag to `chainableMethodWrapper` causes this
                    // function to be the starting point for removing implementation
                    // frames from the stack trace of a failed assertion.
                    //
                    // However, we only want to use this function as the starting point if
                    // the `lockSsfi` flag isn't set.
                    //
                    // If the `lockSsfi` flag is set, then this assertion is being
                    // invoked from inside of another assertion. In this case, the `ssfi`
                    // flag has already been set by the outer assertion.
                    //
                    // Note that overwriting a chainable method merely replaces the saved
                    // methods in `ctx.__methods` instead of completely replacing the
                    // overwritten assertion. Therefore, an overwriting assertion won't
                    // set the `ssfi` or `lockSsfi` flags.
                    if (!flag(this, 'lockSsfi')) {
                      flag(this, 'ssfi', chainableMethodWrapper);
                    }
  
                    var result = chainableBehavior.method.apply(this, arguments);
                    if (result !== undefined) {
                      return result;
                    }
  
                    var newAssertion = new chai.Assertion();
                    transferFlags(this, newAssertion);
                    return newAssertion;
                  };
  
                  addLengthGuard(chainableMethodWrapper, name, true);
  
                  // Use `Object.setPrototypeOf` if available
                  if (canSetPrototype) {
                    // Inherit all properties from the object by replacing the `Function` prototype
                    var prototype = Object.create(this);
                    // Restore the `call` and `apply` methods from `Function`
                    prototype.call = call;
                    prototype.apply = apply;
                    Object.setPrototypeOf(chainableMethodWrapper, prototype);
                  }
                  // Otherwise, redefine all properties (slow!)
                  else {
                    var asserterNames = Object.getOwnPropertyNames(ctx);
                    asserterNames.forEach(function (asserterName) {
                      if (excludeNames.indexOf(asserterName) !== -1) {
                        return;
                      }
  
                      var pd = Object.getOwnPropertyDescriptor(ctx, asserterName);
                      Object.defineProperty(chainableMethodWrapper, asserterName, pd);
                    });
                  }
  
                  transferFlags(this, chainableMethodWrapper);
                  return proxify(chainableMethodWrapper);
                },
                configurable: true,
              });
            };
          },
          {
            '../../chai': 2,
            './addLengthGuard': 10,
            './flag': 15,
            './proxify': 30,
            './transferFlags': 32,
          },
        ],
        10: [
          function (require, module, exports) {
            var fnLengthDesc = Object.getOwnPropertyDescriptor(function () {}, 'length');
  
            /*!
             * Chai - addLengthGuard utility
             * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            /**
             * ### .addLengthGuard(fn, assertionName, isChainable)
             *
             * Define `length` as a getter on the given uninvoked method assertion. The
             * getter acts as a guard against chaining `length` directly off of an uninvoked
             * method assertion, which is a problem because it references `function`'s
             * built-in `length` property instead of Chai's `length` assertion. When the
             * getter catches the user making this mistake, it throws an error with a
             * helpful message.
             *
             * There are two ways in which this mistake can be made. The first way is by
             * chaining the `length` assertion directly off of an uninvoked chainable
             * method. In this case, Chai suggests that the user use `lengthOf` instead. The
             * second way is by chaining the `length` assertion directly off of an uninvoked
             * non-chainable method. Non-chainable methods must be invoked prior to
             * chaining. In this case, Chai suggests that the user consult the docs for the
             * given assertion.
             *
             * If the `length` property of functions is unconfigurable, then return `fn`
             * without modification.
             *
             * Note that in ES6, the function's `length` property is configurable, so once
             * support for legacy environments is dropped, Chai's `length` property can
             * replace the built-in function's `length` property, and this length guard will
             * no longer be necessary. In the mean time, maintaining consistency across all
             * environments is the priority.
             *
             * @param {Function} fn
             * @param {String} assertionName
             * @param {Boolean} isChainable
             * @namespace Utils
             * @name addLengthGuard
             */
  
            module.exports = function addLengthGuard(fn, assertionName, isChainable) {
              if (!fnLengthDesc.configurable) return fn;
  
              Object.defineProperty(fn, 'length', {
                get: function () {
                  if (isChainable) {
                    throw Error(
                      'Invalid Chai property: ' +
                        assertionName +
                        '.length. Due' +
                        ' to a compatibility issue, "length" cannot directly follow "' +
                        assertionName +
                        '". Use "' +
                        assertionName +
                        '.lengthOf" instead.'
                    );
                  }
  
                  throw Error(
                    'Invalid Chai property: ' +
                      assertionName +
                      '.length. See' +
                      ' docs for proper usage of "' +
                      assertionName +
                      '".'
                  );
                },
              });
  
              return fn;
            };
          },
          {},
        ],
        11: [
          function (require, module, exports) {
            /*!
             * Chai - addMethod utility
             * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            var addLengthGuard = require('./addLengthGuard');
            var chai = require('../../chai');
            var flag = require('./flag');
            var proxify = require('./proxify');
            var transferFlags = require('./transferFlags');
  
            /**
             * ### .addMethod(ctx, name, method)
             *
             * Adds a method to the prototype of an object.
             *
             *     utils.addMethod(chai.Assertion.prototype, 'foo', function (str) {
             *       var obj = utils.flag(this, 'object');
             *       new chai.Assertion(obj).to.be.equal(str);
             *     });
             *
             * Can also be accessed directly from `chai.Assertion`.
             *
             *     chai.Assertion.addMethod('foo', fn);
             *
             * Then can be used as any other assertion.
             *
             *     expect(fooStr).to.be.foo('bar');
             *
             * @param {Object} ctx object to which the method is added
             * @param {String} name of method to add
             * @param {Function} method function to be used for name
             * @namespace Utils
             * @name addMethod
             * @api public
             */
  
            module.exports = function addMethod(ctx, name, method) {
              var methodWrapper = function () {
                // Setting the `ssfi` flag to `methodWrapper` causes this function to be the
                // starting point for removing implementation frames from the stack trace of
                // a failed assertion.
                //
                // However, we only want to use this function as the starting point if the
                // `lockSsfi` flag isn't set.
                //
                // If the `lockSsfi` flag is set, then either this assertion has been
                // overwritten by another assertion, or this assertion is being invoked from
                // inside of another assertion. In the first case, the `ssfi` flag has
                // already been set by the overwriting assertion. In the second case, the
                // `ssfi` flag has already been set by the outer assertion.
                if (!flag(this, 'lockSsfi')) {
                  flag(this, 'ssfi', methodWrapper);
                }
  
                var result = method.apply(this, arguments);
                if (result !== undefined) return result;
  
                var newAssertion = new chai.Assertion();
                transferFlags(this, newAssertion);
                return newAssertion;
              };
  
              addLengthGuard(methodWrapper, name, false);
              ctx[name] = proxify(methodWrapper, name);
            };
          },
          {
            '../../chai': 2,
            './addLengthGuard': 10,
            './flag': 15,
            './proxify': 30,
            './transferFlags': 32,
          },
        ],
        12: [
          function (require, module, exports) {
            /*!
             * Chai - addProperty utility
             * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            var chai = require('../../chai');
            var flag = require('./flag');
            var isProxyEnabled = require('./isProxyEnabled');
            var transferFlags = require('./transferFlags');
  
            /**
             * ### .addProperty(ctx, name, getter)
             *
             * Adds a property to the prototype of an object.
             *
             *     utils.addProperty(chai.Assertion.prototype, 'foo', function () {
             *       var obj = utils.flag(this, 'object');
             *       new chai.Assertion(obj).to.be.instanceof(Foo);
             *     });
             *
             * Can also be accessed directly from `chai.Assertion`.
             *
             *     chai.Assertion.addProperty('foo', fn);
             *
             * Then can be used as any other assertion.
             *
             *     expect(myFoo).to.be.foo;
             *
             * @param {Object} ctx object to which the property is added
             * @param {String} name of property to add
             * @param {Function} getter function to be used for name
             * @namespace Utils
             * @name addProperty
             * @api public
             */
  
            module.exports = function addProperty(ctx, name, getter) {
              getter = getter === undefined ? function () {} : getter;
  
              Object.defineProperty(ctx, name, {
                get: function propertyGetter() {
                  // Setting the `ssfi` flag to `propertyGetter` causes this function to
                  // be the starting point for removing implementation frames from the
                  // stack trace of a failed assertion.
                  //
                  // However, we only want to use this function as the starting point if
                  // the `lockSsfi` flag isn't set and proxy protection is disabled.
                  //
                  // If the `lockSsfi` flag is set, then either this assertion has been
                  // overwritten by another assertion, or this assertion is being invoked
                  // from inside of another assertion. In the first case, the `ssfi` flag
                  // has already been set by the overwriting assertion. In the second
                  // case, the `ssfi` flag has already been set by the outer assertion.
                  //
                  // If proxy protection is enabled, then the `ssfi` flag has already been
                  // set by the proxy getter.
                  if (!isProxyEnabled() && !flag(this, 'lockSsfi')) {
                    flag(this, 'ssfi', propertyGetter);
                  }
  
                  var result = getter.call(this);
                  if (result !== undefined) return result;
  
                  var newAssertion = new chai.Assertion();
                  transferFlags(this, newAssertion);
                  return newAssertion;
                },
                configurable: true,
              });
            };
          },
          { '../../chai': 2, './flag': 15, './isProxyEnabled': 25, './transferFlags': 32 },
        ],
        13: [
          function (require, module, exports) {
            /*!
             * Chai - compareByInspect utility
             * Copyright(c) 2011-2016 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            /*!
             * Module dependencies
             */
  
            var inspect = require('./inspect');
  
            /**
             * ### .compareByInspect(mixed, mixed)
             *
             * To be used as a compareFunction with Array.prototype.sort. Compares elements
             * using inspect instead of default behavior of using toString so that Symbols
             * and objects with irregular/missing toString can still be sorted without a
             * TypeError.
             *
             * @param {Mixed} first element to compare
             * @param {Mixed} second element to compare
             * @returns {Number} -1 if 'a' should come before 'b'; otherwise 1
             * @name compareByInspect
             * @namespace Utils
             * @api public
             */
  
            module.exports = function compareByInspect(a, b) {
              return inspect(a) < inspect(b) ? -1 : 1;
            };
          },
          { './inspect': 23 },
        ],
        14: [
          function (require, module, exports) {
            /*!
             * Chai - expectTypes utility
             * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            /**
             * ### .expectTypes(obj, types)
             *
             * Ensures that the object being tested against is of a valid type.
             *
             *     utils.expectTypes(this, ['array', 'object', 'string']);
             *
             * @param {Mixed} obj constructed Assertion
             * @param {Array} type A list of allowed types for this assertion
             * @namespace Utils
             * @name expectTypes
             * @api public
             */
  
            var AssertionError = require('assertion-error');
            var flag = require('./flag');
            var type = require('type-detect');
  
            module.exports = function expectTypes(obj, types) {
              var flagMsg = flag(obj, 'message');
              var ssfi = flag(obj, 'ssfi');
  
              flagMsg = flagMsg ? flagMsg + ': ' : '';
  
              obj = flag(obj, 'object');
              types = types.map(function (t) {
                return t.toLowerCase();
              });
              types.sort();
  
              // Transforms ['lorem', 'ipsum'] into 'a lorem, or an ipsum'
              var str = types
                .map(function (t, index) {
                  var art = ~['a', 'e', 'i', 'o', 'u'].indexOf(t.charAt(0)) ? 'an' : 'a';
                  var or = types.length > 1 && index === types.length - 1 ? 'or ' : '';
                  return or + art + ' ' + t;
                })
                .join(', ');
  
              var objType = type(obj).toLowerCase();
  
              if (
                !types.some(function (expected) {
                  return objType === expected;
                })
              ) {
                throw new AssertionError(
                  flagMsg + 'object tested must be ' + str + ', but ' + objType + ' given',
                  undefined,
                  ssfi
                );
              }
            };
          },
          { './flag': 15, 'assertion-error': 33, 'type-detect': 38 },
        ],
        15: [
          function (require, module, exports) {
            /*!
             * Chai - flag utility
             * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            /**
             * ### .flag(object, key, [value])
             *
             * Get or set a flag value on an object. If a
             * value is provided it will be set, else it will
             * return the currently set value or `undefined` if
             * the value is not set.
             *
             *     utils.flag(this, 'foo', 'bar'); // setter
             *     utils.flag(this, 'foo'); // getter, returns `bar`
             *
             * @param {Object} object constructed Assertion
             * @param {String} key
             * @param {Mixed} value (optional)
             * @namespace Utils
             * @name flag
             * @api private
             */
  
            module.exports = function flag(obj, key, value) {
              var flags = obj.__flags || (obj.__flags = Object.create(null));
              if (arguments.length === 3) {
                flags[key] = value;
              } else {
                return flags[key];
              }
            };
          },
          {},
        ],
        16: [
          function (require, module, exports) {
            /*!
             * Chai - getActual utility
             * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            /**
             * ### .getActual(object, [actual])
             *
             * Returns the `actual` value for an Assertion.
             *
             * @param {Object} object (constructed Assertion)
             * @param {Arguments} chai.Assertion.prototype.assert arguments
             * @namespace Utils
             * @name getActual
             */
  
            module.exports = function getActual(obj, args) {
              return args.length > 4 ? args[4] : obj._obj;
            };
          },
          {},
        ],
        17: [
          function (require, module, exports) {
            /*!
             * Chai - getEnumerableProperties utility
             * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            /**
             * ### .getEnumerableProperties(object)
             *
             * This allows the retrieval of enumerable property names of an object,
             * inherited or not.
             *
             * @param {Object} object
             * @returns {Array}
             * @namespace Utils
             * @name getEnumerableProperties
             * @api public
             */
  
            module.exports = function getEnumerableProperties(object) {
              var result = [];
              for (var name in object) {
                result.push(name);
              }
              return result;
            };
          },
          {},
        ],
        18: [
          function (require, module, exports) {
            /*!
             * Chai - message composition utility
             * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            /*!
             * Module dependencies
             */
  
            var flag = require('./flag'),
              getActual = require('./getActual'),
              objDisplay = require('./objDisplay');
  
            /**
             * ### .getMessage(object, message, negateMessage)
             *
             * Construct the error message based on flags
             * and template tags. Template tags will return
             * a stringified inspection of the object referenced.
             *
             * Message template tags:
             * - `#{this}` current asserted object
             * - `#{act}` actual value
             * - `#{exp}` expected value
             *
             * @param {Object} object (constructed Assertion)
             * @param {Arguments} chai.Assertion.prototype.assert arguments
             * @namespace Utils
             * @name getMessage
             * @api public
             */
  
            module.exports = function getMessage(obj, args) {
              var negate = flag(obj, 'negate'),
                val = flag(obj, 'object'),
                expected = args[3],
                actual = getActual(obj, args),
                msg = negate ? args[2] : args[1],
                flagMsg = flag(obj, 'message');
  
              if (typeof msg === 'function') msg = msg();
              msg = msg || '';
              msg = msg
                .replace(/#\{this\}/g, function () {
                  return objDisplay(val);
                })
                .replace(/#\{act\}/g, function () {
                  return objDisplay(actual);
                })
                .replace(/#\{exp\}/g, function () {
                  return objDisplay(expected);
                });
  
              return flagMsg ? flagMsg + ': ' + msg : msg;
            };
          },
          { './flag': 15, './getActual': 16, './objDisplay': 26 },
        ],
        19: [
          function (require, module, exports) {
            /*!
             * Chai - getOwnEnumerableProperties utility
             * Copyright(c) 2011-2016 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            /*!
             * Module dependencies
             */
  
            var getOwnEnumerablePropertySymbols = require('./getOwnEnumerablePropertySymbols');
  
            /**
             * ### .getOwnEnumerableProperties(object)
             *
             * This allows the retrieval of directly-owned enumerable property names and
             * symbols of an object. This function is necessary because Object.keys only
             * returns enumerable property names, not enumerable property symbols.
             *
             * @param {Object} object
             * @returns {Array}
             * @namespace Utils
             * @name getOwnEnumerableProperties
             * @api public
             */
  
            module.exports = function getOwnEnumerableProperties(obj) {
              return Object.keys(obj).concat(getOwnEnumerablePropertySymbols(obj));
            };
          },
          { './getOwnEnumerablePropertySymbols': 20 },
        ],
        20: [
          function (require, module, exports) {
            /*!
             * Chai - getOwnEnumerablePropertySymbols utility
             * Copyright(c) 2011-2016 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            /**
             * ### .getOwnEnumerablePropertySymbols(object)
             *
             * This allows the retrieval of directly-owned enumerable property symbols of an
             * object. This function is necessary because Object.getOwnPropertySymbols
             * returns both enumerable and non-enumerable property symbols.
             *
             * @param {Object} object
             * @returns {Array}
             * @namespace Utils
             * @name getOwnEnumerablePropertySymbols
             * @api public
             */
  
            module.exports = function getOwnEnumerablePropertySymbols(obj) {
              if (typeof Object.getOwnPropertySymbols !== 'function') return [];
  
              return Object.getOwnPropertySymbols(obj).filter(function (sym) {
                return Object.getOwnPropertyDescriptor(obj, sym).enumerable;
              });
            };
          },
          {},
        ],
        21: [
          function (require, module, exports) {
            /*!
             * Chai - getProperties utility
             * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            /**
             * ### .getProperties(object)
             *
             * This allows the retrieval of property names of an object, enumerable or not,
             * inherited or not.
             *
             * @param {Object} object
             * @returns {Array}
             * @namespace Utils
             * @name getProperties
             * @api public
             */
  
            module.exports = function getProperties(object) {
              var result = Object.getOwnPropertyNames(object);
  
              function addProperty(property) {
                if (result.indexOf(property) === -1) {
                  result.push(property);
                }
              }
  
              var proto = Object.getPrototypeOf(object);
              while (proto !== null) {
                Object.getOwnPropertyNames(proto).forEach(addProperty);
                proto = Object.getPrototypeOf(proto);
              }
  
              return result;
            };
          },
          {},
        ],
        22: [
          function (require, module, exports) {
            /*!
             * chai
             * Copyright(c) 2011 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            /*!
             * Dependencies that are used for multiple exports are required here only once
             */
  
            var pathval = require('pathval');
  
            /*!
             * test utility
             */
  
            exports.test = require('./test');
  
            /*!
             * type utility
             */
  
            exports.type = require('type-detect');
  
            /*!
             * expectTypes utility
             */
            exports.expectTypes = require('./expectTypes');
  
            /*!
             * message utility
             */
  
            exports.getMessage = require('./getMessage');
  
            /*!
             * actual utility
             */
  
            exports.getActual = require('./getActual');
  
            /*!
             * Inspect util
             */
  
            exports.inspect = require('./inspect');
  
            /*!
             * Object Display util
             */
  
            exports.objDisplay = require('./objDisplay');
  
            /*!
             * Flag utility
             */
  
            exports.flag = require('./flag');
  
            /*!
             * Flag transferring utility
             */
  
            exports.transferFlags = require('./transferFlags');
  
            /*!
             * Deep equal utility
             */
  
            exports.eql = require('deep-eql');
  
            /*!
             * Deep path info
             */
  
            exports.getPathInfo = pathval.getPathInfo;
  
            /*!
             * Check if a property exists
             */
  
            exports.hasProperty = pathval.hasProperty;
  
            /*!
             * Function name
             */
  
            exports.getName = require('get-func-name');
  
            /*!
             * add Property
             */
  
            exports.addProperty = require('./addProperty');
  
            /*!
             * add Method
             */
  
            exports.addMethod = require('./addMethod');
  
            /*!
             * overwrite Property
             */
  
            exports.overwriteProperty = require('./overwriteProperty');
  
            /*!
             * overwrite Method
             */
  
            exports.overwriteMethod = require('./overwriteMethod');
  
            /*!
             * Add a chainable method
             */
  
            exports.addChainableMethod = require('./addChainableMethod');
  
            /*!
             * Overwrite chainable method
             */
  
            exports.overwriteChainableMethod = require('./overwriteChainableMethod');
  
            /*!
             * Compare by inspect method
             */
  
            exports.compareByInspect = require('./compareByInspect');
  
            /*!
             * Get own enumerable property symbols method
             */
  
            exports.getOwnEnumerablePropertySymbols = require('./getOwnEnumerablePropertySymbols');
  
            /*!
             * Get own enumerable properties method
             */
  
            exports.getOwnEnumerableProperties = require('./getOwnEnumerableProperties');
  
            /*!
             * Checks error against a given set of criteria
             */
  
            exports.checkError = require('check-error');
  
            /*!
             * Proxify util
             */
  
            exports.proxify = require('./proxify');
  
            /*!
             * addLengthGuard util
             */
  
            exports.addLengthGuard = require('./addLengthGuard');
  
            /*!
             * isProxyEnabled helper
             */
  
            exports.isProxyEnabled = require('./isProxyEnabled');
  
            /*!
             * isNaN method
             */
  
            exports.isNaN = require('./isNaN');
          },
          {
            './addChainableMethod': 9,
            './addLengthGuard': 10,
            './addMethod': 11,
            './addProperty': 12,
            './compareByInspect': 13,
            './expectTypes': 14,
            './flag': 15,
            './getActual': 16,
            './getMessage': 18,
            './getOwnEnumerableProperties': 19,
            './getOwnEnumerablePropertySymbols': 20,
            './inspect': 23,
            './isNaN': 24,
            './isProxyEnabled': 25,
            './objDisplay': 26,
            './overwriteChainableMethod': 27,
            './overwriteMethod': 28,
            './overwriteProperty': 29,
            './proxify': 30,
            './test': 31,
            './transferFlags': 32,
            'check-error': 34,
            'deep-eql': 35,
            'get-func-name': 36,
            pathval: 37,
            'type-detect': 38,
          },
        ],
        23: [
          function (require, module, exports) {
            // This is (almost) directly from Node.js utils
            // https://github.com/joyent/node/blob/f8c335d0caf47f16d31413f89aa28eda3878e3aa/lib/util.js
  
            var getName = require('get-func-name');
            var getProperties = require('./getProperties');
            var getEnumerableProperties = require('./getEnumerableProperties');
            var config = require('../config');
  
            module.exports = inspect;
  
            /**
             * ### .inspect(obj, [showHidden], [depth], [colors])
             *
             * Echoes the value of a value. Tries to print the value out
             * in the best way possible given the different types.
             *
             * @param {Object} obj The object to print out.
             * @param {Boolean} showHidden Flag that shows hidden (not enumerable)
             *    properties of objects. Default is false.
             * @param {Number} depth Depth in which to descend in object. Default is 2.
             * @param {Boolean} colors Flag to turn on ANSI escape codes to color the
             *    output. Default is false (no coloring).
             * @namespace Utils
             * @name inspect
             */
            function inspect(obj, showHidden, depth, colors) {
              var ctx = {
                showHidden: showHidden,
                seen: [],
                stylize: function (str) {
                  return str;
                },
              };
              return formatValue(ctx, obj, typeof depth === 'undefined' ? 2 : depth);
            }
  
            // Returns true if object is a DOM element.
            var isDOMElement = function (object) {
              if (typeof HTMLElement === 'object') {
                return object instanceof HTMLElement;
              } else {
                return (
                  object &&
                  typeof object === 'object' &&
                  'nodeType' in object &&
                  object.nodeType === 1 &&
                  typeof object.nodeName === 'string'
                );
              }
            };
  
            function formatValue(ctx, value, recurseTimes) {
              // Provide a hook for user-specified inspect functions.
              // Check that value is an object with an inspect function on it
              if (
                value &&
                typeof value.inspect === 'function' &&
                // Filter out the util module, it's inspect function is special
                value.inspect !== exports.inspect &&
                // Also filter out any prototype objects using the circular check.
                !(value.constructor && value.constructor.prototype === value)
              ) {
                var ret = value.inspect(recurseTimes, ctx);
                if (typeof ret !== 'string') {
                  ret = formatValue(ctx, ret, recurseTimes);
                }
                return ret;
              }
  
              // Primitive types cannot have properties
              var primitive = formatPrimitive(ctx, value);
              if (primitive) {
                return primitive;
              }
  
              // If this is a DOM element, try to get the outer HTML.
              if (isDOMElement(value)) {
                if ('outerHTML' in value) {
                  return value.outerHTML;
                  // This value does not have an outerHTML attribute,
                  //   it could still be an XML element
                } else {
                  // Attempt to serialize it
                  try {
                    if (document.xmlVersion) {
                      var xmlSerializer = new XMLSerializer();
                      return xmlSerializer.serializeToString(value);
                    } else {
                      // Firefox 11- do not support outerHTML
                      //   It does, however, support innerHTML
                      //   Use the following to render the element
                      var ns = 'http://www.w3.org/1999/xhtml';
                      var container = document.createElementNS(ns, '_');
  
                      container.appendChild(value.cloneNode(false));
                      var html = container.innerHTML.replace('><', '>' + value.innerHTML + '<');
                      container.innerHTML = '';
                      return html;
                    }
                  } catch (err) {
                    // This could be a non-native DOM implementation,
                    //   continue with the normal flow:
                    //   printing the element as if it is an object.
                  }
                }
              }
  
              // Look up the keys of the object.
              var visibleKeys = getEnumerableProperties(value);
              var keys = ctx.showHidden ? getProperties(value) : visibleKeys;
  
              var name, nameSuffix;
  
              // Some type of object without properties can be shortcut.
              // In IE, errors have a single `stack` property, or if they are vanilla `Error`,
              // a `stack` plus `description` property; ignore those for consistency.
              if (
                keys.length === 0 ||
                (isError(value) &&
                  ((keys.length === 1 && keys[0] === 'stack') ||
                    (keys.length === 2 && keys[0] === 'description' && keys[1] === 'stack')))
              ) {
                if (typeof value === 'function') {
                  name = getName(value);
                  nameSuffix = name ? ': ' + name : '';
                  return ctx.stylize('[Function' + nameSuffix + ']', 'special');
                }
                if (isRegExp(value)) {
                  return ctx.stylize(RegExp.prototype.toString.call(value), 'regexp');
                }
                if (isDate(value)) {
                  return ctx.stylize(Date.prototype.toUTCString.call(value), 'date');
                }
                if (isError(value)) {
                  return formatError(value);
                }
              }
  
              var base = '',
                array = false,
                typedArray = false,
                braces = ['{', '}'];
  
              if (isTypedArray(value)) {
                typedArray = true;
                braces = ['[', ']'];
              }
  
              // Make Array say that they are Array
              if (isArray(value)) {
                array = true;
                braces = ['[', ']'];
              }
  
              // Make functions say that they are functions
              if (typeof value === 'function') {
                name = getName(value);
                nameSuffix = name ? ': ' + name : '';
                base = ' [Function' + nameSuffix + ']';
              }
  
              // Make RegExps say that they are RegExps
              if (isRegExp(value)) {
                base = ' ' + RegExp.prototype.toString.call(value);
              }
  
              // Make dates with properties first say the date
              if (isDate(value)) {
                base = ' ' + Date.prototype.toUTCString.call(value);
              }
  
              // Make error with message first say the error
              if (isError(value)) {
                return formatError(value);
              }
  
              if (keys.length === 0 && (!array || value.length == 0)) {
                return braces[0] + base + braces[1];
              }
  
              if (recurseTimes < 0) {
                if (isRegExp(value)) {
                  return ctx.stylize(RegExp.prototype.toString.call(value), 'regexp');
                } else {
                  return ctx.stylize('[Object]', 'special');
                }
              }
  
              ctx.seen.push(value);
  
              var output;
              if (array) {
                output = formatArray(ctx, value, recurseTimes, visibleKeys, keys);
              } else if (typedArray) {
                return formatTypedArray(value);
              } else {
                output = keys.map(function (key) {
                  return formatProperty(ctx, value, recurseTimes, visibleKeys, key, array);
                });
              }
  
              ctx.seen.pop();
  
              return reduceToSingleString(output, base, braces);
            }
  
            function formatPrimitive(ctx, value) {
              switch (typeof value) {
                case 'undefined':
                  return ctx.stylize('undefined', 'undefined');
  
                case 'string':
                  var simple =
                    "'" +
                    JSON.stringify(value)
                      .replace(/^"|"$/g, '')
                      .replace(/'/g, "\\'")
                      .replace(/\\"/g, '"') +
                    "'";
                  return ctx.stylize(simple, 'string');
  
                case 'number':
                  if (value === 0 && 1 / value === -Infinity) {
                    return ctx.stylize('-0', 'number');
                  }
                  return ctx.stylize('' + value, 'number');
  
                case 'boolean':
                  return ctx.stylize('' + value, 'boolean');
  
                case 'symbol':
                  return ctx.stylize(value.toString(), 'symbol');
              }
              // For some reason typeof null is "object", so special case here.
              if (value === null) {
                return ctx.stylize('null', 'null');
              }
            }
  
            function formatError(value) {
              return '[' + Error.prototype.toString.call(value) + ']';
            }
  
            function formatArray(ctx, value, recurseTimes, visibleKeys, keys) {
              var output = [];
              for (var i = 0, l = value.length; i < l; ++i) {
                if (Object.prototype.hasOwnProperty.call(value, String(i))) {
                  output.push(formatProperty(ctx, value, recurseTimes, visibleKeys, String(i), true));
                } else {
                  output.push('');
                }
              }
  
              keys.forEach(function (key) {
                if (!key.match(/^\d+$/)) {
                  output.push(formatProperty(ctx, value, recurseTimes, visibleKeys, key, true));
                }
              });
              return output;
            }
  
            function formatTypedArray(value) {
              var str = '[ ';
  
              for (var i = 0; i < value.length; ++i) {
                if (str.length >= config.truncateThreshold - 7) {
                  str += '...';
                  break;
                }
                str += value[i] + ', ';
              }
              str += ' ]';
  
              // Removing trailing `, ` if the array was not truncated
              if (str.indexOf(',  ]') !== -1) {
                str = str.replace(',  ]', ' ]');
              }
  
              return str;
            }
  
            function formatProperty(ctx, value, recurseTimes, visibleKeys, key, array) {
              var name;
              var propDescriptor = Object.getOwnPropertyDescriptor(value, key);
              var str;
  
              if (propDescriptor) {
                if (propDescriptor.get) {
                  if (propDescriptor.set) {
                    str = ctx.stylize('[Getter/Setter]', 'special');
                  } else {
                    str = ctx.stylize('[Getter]', 'special');
                  }
                } else {
                  if (propDescriptor.set) {
                    str = ctx.stylize('[Setter]', 'special');
                  }
                }
              }
              if (visibleKeys.indexOf(key) < 0) {
                name = '[' + key + ']';
              }
              if (!str) {
                if (ctx.seen.indexOf(value[key]) < 0) {
                  if (recurseTimes === null) {
                    str = formatValue(ctx, value[key], null);
                  } else {
                    str = formatValue(ctx, value[key], recurseTimes - 1);
                  }
                  if (str.indexOf('\n') > -1) {
                    if (array) {
                      str = str
                        .split('\n')
                        .map(function (line) {
                          return '  ' + line;
                        })
                        .join('\n')
                        .substr(2);
                    } else {
                      str =
                        '\n' +
                        str
                          .split('\n')
                          .map(function (line) {
                            return '   ' + line;
                          })
                          .join('\n');
                    }
                  }
                } else {
                  str = ctx.stylize('[Circular]', 'special');
                }
              }
              if (typeof name === 'undefined') {
                if (array && key.match(/^\d+$/)) {
                  return str;
                }
                name = JSON.stringify('' + key);
                if (name.match(/^"([a-zA-Z_][a-zA-Z_0-9]*)"$/)) {
                  name = name.substr(1, name.length - 2);
                  name = ctx.stylize(name, 'name');
                } else {
                  name = name
                    .replace(/'/g, "\\'")
                    .replace(/\\"/g, '"')
                    .replace(/(^"|"$)/g, "'");
                  name = ctx.stylize(name, 'string');
                }
              }
  
              return name + ': ' + str;
            }
  
            function reduceToSingleString(output, base, braces) {
              var length = output.reduce(function (prev, cur) {
                return prev + cur.length + 1;
              }, 0);
  
              if (length > 60) {
                return (
                  braces[0] +
                  (base === '' ? '' : base + '\n ') +
                  ' ' +
                  output.join(',\n  ') +
                  ' ' +
                  braces[1]
                );
              }
  
              return braces[0] + base + ' ' + output.join(', ') + ' ' + braces[1];
            }
  
            function isTypedArray(ar) {
              // Unfortunately there's no way to check if an object is a TypedArray
              // We have to check if it's one of these types
              return typeof ar === 'object' && /\w+Array]$/.test(objectToString(ar));
            }
  
            function isArray(ar) {
              return (
                Array.isArray(ar) ||
                (typeof ar === 'object' && objectToString(ar) === '[object Array]')
              );
            }
  
            function isRegExp(re) {
              return typeof re === 'object' && objectToString(re) === '[object RegExp]';
            }
  
            function isDate(d) {
              return typeof d === 'object' && objectToString(d) === '[object Date]';
            }
  
            function isError(e) {
              return typeof e === 'object' && objectToString(e) === '[object Error]';
            }
  
            function objectToString(o) {
              return Object.prototype.toString.call(o);
            }
          },
          {
            '../config': 4,
            './getEnumerableProperties': 17,
            './getProperties': 21,
            'get-func-name': 36,
          },
        ],
        24: [
          function (require, module, exports) {
            /*!
             * Chai - isNaN utility
             * Copyright(c) 2012-2015 Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
             * MIT Licensed
             */
  
            /**
             * ### .isNaN(value)
             *
             * Checks if the given value is NaN or not.
             *
             *     utils.isNaN(NaN); // true
             *
             * @param {Value} The value which has to be checked if it is NaN
             * @name isNaN
             * @api private
             */
  
            function isNaN(value) {
              // Refer http://www.ecma-international.org/ecma-262/6.0/#sec-isnan-number
              // section's NOTE.
              return value !== value;
            }
  
            // If ECMAScript 6's Number.isNaN is present, prefer that.
            module.exports = Number.isNaN || isNaN;
          },
          {},
        ],
        25: [
          function (require, module, exports) {
            var config = require('../config');
  
            /*!
             * Chai - isProxyEnabled helper
             * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            /**
             * ### .isProxyEnabled()
             *
             * Helper function to check if Chai's proxy protection feature is enabled. If
             * proxies are unsupported or disabled via the user's Chai config, then return
             * false. Otherwise, return true.
             *
             * @namespace Utils
             * @name isProxyEnabled
             */
  
            module.exports = function isProxyEnabled() {
              return (
                config.useProxy && typeof Proxy !== 'undefined' && typeof Reflect !== 'undefined'
              );
            };
          },
          { '../config': 4 },
        ],
        26: [
          function (require, module, exports) {
            /*!
             * Chai - flag utility
             * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            /*!
             * Module dependencies
             */
  
            var inspect = require('./inspect');
            var config = require('../config');
  
            /**
             * ### .objDisplay(object)
             *
             * Determines if an object or an array matches
             * criteria to be inspected in-line for error
             * messages or should be truncated.
             *
             * @param {Mixed} javascript object to inspect
             * @name objDisplay
             * @namespace Utils
             * @api public
             */
  
            module.exports = function objDisplay(obj) {
              var str = inspect(obj),
                type = Object.prototype.toString.call(obj);
  
              if (config.truncateThreshold && str.length >= config.truncateThreshold) {
                if (type === '[object Function]') {
                  return !obj.name || obj.name === '' ? '[Function]' : '[Function: ' + obj.name + ']';
                } else if (type === '[object Array]') {
                  return '[ Array(' + obj.length + ') ]';
                } else if (type === '[object Object]') {
                  var keys = Object.keys(obj),
                    kstr = keys.length > 2 ? keys.splice(0, 2).join(', ') + ', ...' : keys.join(', ');
                  return '{ Object (' + kstr + ') }';
                } else {
                  return str;
                }
              } else {
                return str;
              }
            };
          },
          { '../config': 4, './inspect': 23 },
        ],
        27: [
          function (require, module, exports) {
            /*!
             * Chai - overwriteChainableMethod utility
             * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            var chai = require('../../chai');
            var transferFlags = require('./transferFlags');
  
            /**
             * ### .overwriteChainableMethod(ctx, name, method, chainingBehavior)
             *
             * Overwrites an already existing chainable method
             * and provides access to the previous function or
             * property.  Must return functions to be used for
             * name.
             *
             *     utils.overwriteChainableMethod(chai.Assertion.prototype, 'lengthOf',
             *       function (_super) {
             *       }
             *     , function (_super) {
             *       }
             *     );
             *
             * Can also be accessed directly from `chai.Assertion`.
             *
             *     chai.Assertion.overwriteChainableMethod('foo', fn, fn);
             *
             * Then can be used as any other assertion.
             *
             *     expect(myFoo).to.have.lengthOf(3);
             *     expect(myFoo).to.have.lengthOf.above(3);
             *
             * @param {Object} ctx object whose method / property is to be overwritten
             * @param {String} name of method / property to overwrite
             * @param {Function} method function that returns a function to be used for name
             * @param {Function} chainingBehavior function that returns a function to be used for property
             * @namespace Utils
             * @name overwriteChainableMethod
             * @api public
             */
  
            module.exports = function overwriteChainableMethod(ctx, name, method, chainingBehavior) {
              var chainableBehavior = ctx.__methods[name];
  
              var _chainingBehavior = chainableBehavior.chainingBehavior;
              chainableBehavior.chainingBehavior = function overwritingChainableMethodGetter() {
                var result = chainingBehavior(_chainingBehavior).call(this);
                if (result !== undefined) {
                  return result;
                }
  
                var newAssertion = new chai.Assertion();
                transferFlags(this, newAssertion);
                return newAssertion;
              };
  
              var _method = chainableBehavior.method;
              chainableBehavior.method = function overwritingChainableMethodWrapper() {
                var result = method(_method).apply(this, arguments);
                if (result !== undefined) {
                  return result;
                }
  
                var newAssertion = new chai.Assertion();
                transferFlags(this, newAssertion);
                return newAssertion;
              };
            };
          },
          { '../../chai': 2, './transferFlags': 32 },
        ],
        28: [
          function (require, module, exports) {
            /*!
             * Chai - overwriteMethod utility
             * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            var addLengthGuard = require('./addLengthGuard');
            var chai = require('../../chai');
            var flag = require('./flag');
            var proxify = require('./proxify');
            var transferFlags = require('./transferFlags');
  
            /**
             * ### .overwriteMethod(ctx, name, fn)
             *
             * Overwrites an already existing method and provides
             * access to previous function. Must return function
             * to be used for name.
             *
             *     utils.overwriteMethod(chai.Assertion.prototype, 'equal', function (_super) {
             *       return function (str) {
             *         var obj = utils.flag(this, 'object');
             *         if (obj instanceof Foo) {
             *           new chai.Assertion(obj.value).to.equal(str);
             *         } else {
             *           _super.apply(this, arguments);
             *         }
             *       }
             *     });
             *
             * Can also be accessed directly from `chai.Assertion`.
             *
             *     chai.Assertion.overwriteMethod('foo', fn);
             *
             * Then can be used as any other assertion.
             *
             *     expect(myFoo).to.equal('bar');
             *
             * @param {Object} ctx object whose method is to be overwritten
             * @param {String} name of method to overwrite
             * @param {Function} method function that returns a function to be used for name
             * @namespace Utils
             * @name overwriteMethod
             * @api public
             */
  
            module.exports = function overwriteMethod(ctx, name, method) {
              var _method = ctx[name],
                _super = function () {
                  throw new Error(name + ' is not a function');
                };
  
              if (_method && 'function' === typeof _method) _super = _method;
  
              var overwritingMethodWrapper = function () {
                // Setting the `ssfi` flag to `overwritingMethodWrapper` causes this
                // function to be the starting point for removing implementation frames from
                // the stack trace of a failed assertion.
                //
                // However, we only want to use this function as the starting point if the
                // `lockSsfi` flag isn't set.
                //
                // If the `lockSsfi` flag is set, then either this assertion has been
                // overwritten by another assertion, or this assertion is being invoked from
                // inside of another assertion. In the first case, the `ssfi` flag has
                // already been set by the overwriting assertion. In the second case, the
                // `ssfi` flag has already been set by the outer assertion.
                if (!flag(this, 'lockSsfi')) {
                  flag(this, 'ssfi', overwritingMethodWrapper);
                }
  
                // Setting the `lockSsfi` flag to `true` prevents the overwritten assertion
                // from changing the `ssfi` flag. By this point, the `ssfi` flag is already
                // set to the correct starting point for this assertion.
                var origLockSsfi = flag(this, 'lockSsfi');
                flag(this, 'lockSsfi', true);
                var result = method(_super).apply(this, arguments);
                flag(this, 'lockSsfi', origLockSsfi);
  
                if (result !== undefined) {
                  return result;
                }
  
                var newAssertion = new chai.Assertion();
                transferFlags(this, newAssertion);
                return newAssertion;
              };
  
              addLengthGuard(overwritingMethodWrapper, name, false);
              ctx[name] = proxify(overwritingMethodWrapper, name);
            };
          },
          {
            '../../chai': 2,
            './addLengthGuard': 10,
            './flag': 15,
            './proxify': 30,
            './transferFlags': 32,
          },
        ],
        29: [
          function (require, module, exports) {
            /*!
             * Chai - overwriteProperty utility
             * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            var chai = require('../../chai');
            var flag = require('./flag');
            var isProxyEnabled = require('./isProxyEnabled');
            var transferFlags = require('./transferFlags');
  
            /**
             * ### .overwriteProperty(ctx, name, fn)
             *
             * Overwrites an already existing property getter and provides
             * access to previous value. Must return function to use as getter.
             *
             *     utils.overwriteProperty(chai.Assertion.prototype, 'ok', function (_super) {
             *       return function () {
             *         var obj = utils.flag(this, 'object');
             *         if (obj instanceof Foo) {
             *           new chai.Assertion(obj.name).to.equal('bar');
             *         } else {
             *           _super.call(this);
             *         }
             *       }
             *     });
             *
             *
             * Can also be accessed directly from `chai.Assertion`.
             *
             *     chai.Assertion.overwriteProperty('foo', fn);
             *
             * Then can be used as any other assertion.
             *
             *     expect(myFoo).to.be.ok;
             *
             * @param {Object} ctx object whose property is to be overwritten
             * @param {String} name of property to overwrite
             * @param {Function} getter function that returns a getter function to be used for name
             * @namespace Utils
             * @name overwriteProperty
             * @api public
             */
  
            module.exports = function overwriteProperty(ctx, name, getter) {
              var _get = Object.getOwnPropertyDescriptor(ctx, name),
                _super = function () {};
  
              if (_get && 'function' === typeof _get.get) _super = _get.get;
  
              Object.defineProperty(ctx, name, {
                get: function overwritingPropertyGetter() {
                  // Setting the `ssfi` flag to `overwritingPropertyGetter` causes this
                  // function to be the starting point for removing implementation frames
                  // from the stack trace of a failed assertion.
                  //
                  // However, we only want to use this function as the starting point if
                  // the `lockSsfi` flag isn't set and proxy protection is disabled.
                  //
                  // If the `lockSsfi` flag is set, then either this assertion has been
                  // overwritten by another assertion, or this assertion is being invoked
                  // from inside of another assertion. In the first case, the `ssfi` flag
                  // has already been set by the overwriting assertion. In the second
                  // case, the `ssfi` flag has already been set by the outer assertion.
                  //
                  // If proxy protection is enabled, then the `ssfi` flag has already been
                  // set by the proxy getter.
                  if (!isProxyEnabled() && !flag(this, 'lockSsfi')) {
                    flag(this, 'ssfi', overwritingPropertyGetter);
                  }
  
                  // Setting the `lockSsfi` flag to `true` prevents the overwritten
                  // assertion from changing the `ssfi` flag. By this point, the `ssfi`
                  // flag is already set to the correct starting point for this assertion.
                  var origLockSsfi = flag(this, 'lockSsfi');
                  flag(this, 'lockSsfi', true);
                  var result = getter(_super).call(this);
                  flag(this, 'lockSsfi', origLockSsfi);
  
                  if (result !== undefined) {
                    return result;
                  }
  
                  var newAssertion = new chai.Assertion();
                  transferFlags(this, newAssertion);
                  return newAssertion;
                },
                configurable: true,
              });
            };
          },
          { '../../chai': 2, './flag': 15, './isProxyEnabled': 25, './transferFlags': 32 },
        ],
        30: [
          function (require, module, exports) {
            var config = require('../config');
            var flag = require('./flag');
            var getProperties = require('./getProperties');
            var isProxyEnabled = require('./isProxyEnabled');
  
            /*!
             * Chai - proxify utility
             * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            /**
             * ### .proxify(object)
             *
             * Return a proxy of given object that throws an error when a non-existent
             * property is read. By default, the root cause is assumed to be a misspelled
             * property, and thus an attempt is made to offer a reasonable suggestion from
             * the list of existing properties. However, if a nonChainableMethodName is
             * provided, then the root cause is instead a failure to invoke a non-chainable
             * method prior to reading the non-existent property.
             *
             * If proxies are unsupported or disabled via the user's Chai config, then
             * return object without modification.
             *
             * @param {Object} obj
             * @param {String} nonChainableMethodName
             * @namespace Utils
             * @name proxify
             */
  
            var builtins = ['__flags', '__methods', '_obj', 'assert'];
  
            module.exports = function proxify(obj, nonChainableMethodName) {
              if (!isProxyEnabled()) return obj;
  
              return new Proxy(obj, {
                get: function proxyGetter(target, property) {
                  // This check is here because we should not throw errors on Symbol properties
                  // such as `Symbol.toStringTag`.
                  // The values for which an error should be thrown can be configured using
                  // the `config.proxyExcludedKeys` setting.
                  if (
                    typeof property === 'string' &&
                    config.proxyExcludedKeys.indexOf(property) === -1 &&
                    !Reflect.has(target, property)
                  ) {
                    // Special message for invalid property access of non-chainable methods.
                    if (nonChainableMethodName) {
                      throw Error(
                        'Invalid Chai property: ' +
                          nonChainableMethodName +
                          '.' +
                          property +
                          '. See docs for proper usage of "' +
                          nonChainableMethodName +
                          '".'
                      );
                    }
  
                    // If the property is reasonably close to an existing Chai property,
                    // suggest that property to the user. Only suggest properties with a
                    // distance less than 4.
                    var suggestion = null;
                    var suggestionDistance = 4;
                    getProperties(target).forEach(function (prop) {
                      if (!Object.prototype.hasOwnProperty(prop) && builtins.indexOf(prop) === -1) {
                        var dist = stringDistanceCapped(property, prop, suggestionDistance);
                        if (dist < suggestionDistance) {
                          suggestion = prop;
                          suggestionDistance = dist;
                        }
                      }
                    });
  
                    if (suggestion !== null) {
                      throw Error(
                        'Invalid Chai property: ' + property + '. Did you mean "' + suggestion + '"?'
                      );
                    } else {
                      throw Error('Invalid Chai property: ' + property);
                    }
                  }
  
                  // Use this proxy getter as the starting point for removing implementation
                  // frames from the stack trace of a failed assertion. For property
                  // assertions, this prevents the proxy getter from showing up in the stack
                  // trace since it's invoked before the property getter. For method and
                  // chainable method assertions, this flag will end up getting changed to
                  // the method wrapper, which is good since this frame will no longer be in
                  // the stack once the method is invoked. Note that Chai builtin assertion
                  // properties such as `__flags` are skipped since this is only meant to
                  // capture the starting point of an assertion. This step is also skipped
                  // if the `lockSsfi` flag is set, thus indicating that this assertion is
                  // being called from within another assertion. In that case, the `ssfi`
                  // flag is already set to the outer assertion's starting point.
                  if (builtins.indexOf(property) === -1 && !flag(target, 'lockSsfi')) {
                    flag(target, 'ssfi', proxyGetter);
                  }
  
                  return Reflect.get(target, property);
                },
              });
            };
  
            /**
             * # stringDistanceCapped(strA, strB, cap)
             * Return the Levenshtein distance between two strings, but no more than cap.
             * @param {string} strA
             * @param {string} strB
             * @param {number} number
             * @return {number} min(string distance between strA and strB, cap)
             * @api private
             */
  
            function stringDistanceCapped(strA, strB, cap) {
              if (Math.abs(strA.length - strB.length) >= cap) {
                return cap;
              }
  
              var memo = [];
              // `memo` is a two-dimensional array containing distances.
              // memo[i][j] is the distance between strA.slice(0, i) and
              // strB.slice(0, j).
              for (var i = 0; i <= strA.length; i++) {
                memo[i] = Array(strB.length + 1).fill(0);
                memo[i][0] = i;
              }
              for (var j = 0; j < strB.length; j++) {
                memo[0][j] = j;
              }
  
              for (var i = 1; i <= strA.length; i++) {
                var ch = strA.charCodeAt(i - 1);
                for (var j = 1; j <= strB.length; j++) {
                  if (Math.abs(i - j) >= cap) {
                    memo[i][j] = cap;
                    continue;
                  }
                  memo[i][j] = Math.min(
                    memo[i - 1][j] + 1,
                    memo[i][j - 1] + 1,
                    memo[i - 1][j - 1] + (ch === strB.charCodeAt(j - 1) ? 0 : 1)
                  );
                }
              }
  
              return memo[strA.length][strB.length];
            }
          },
          { '../config': 4, './flag': 15, './getProperties': 21, './isProxyEnabled': 25 },
        ],
        31: [
          function (require, module, exports) {
            /*!
             * Chai - test utility
             * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            /*!
             * Module dependencies
             */
  
            var flag = require('./flag');
  
            /**
             * ### .test(object, expression)
             *
             * Test and object for expression.
             *
             * @param {Object} object (constructed Assertion)
             * @param {Arguments} chai.Assertion.prototype.assert arguments
             * @namespace Utils
             * @name test
             */
  
            module.exports = function test(obj, args) {
              var negate = flag(obj, 'negate'),
                expr = args[0];
              return negate ? !expr : expr;
            };
          },
          { './flag': 15 },
        ],
        32: [
          function (require, module, exports) {
            /*!
             * Chai - transferFlags utility
             * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            /**
             * ### .transferFlags(assertion, object, includeAll = true)
             *
             * Transfer all the flags for `assertion` to `object`. If
             * `includeAll` is set to `false`, then the base Chai
             * assertion flags (namely `object`, `ssfi`, `lockSsfi`,
             * and `message`) will not be transferred.
             *
             *
             *     var newAssertion = new Assertion();
             *     utils.transferFlags(assertion, newAssertion);
             *
             *     var anotherAssertion = new Assertion(myObj);
             *     utils.transferFlags(assertion, anotherAssertion, false);
             *
             * @param {Assertion} assertion the assertion to transfer the flags from
             * @param {Object} object the object to transfer the flags to; usually a new assertion
             * @param {Boolean} includeAll
             * @namespace Utils
             * @name transferFlags
             * @api private
             */
  
            module.exports = function transferFlags(assertion, object, includeAll) {
              var flags = assertion.__flags || (assertion.__flags = Object.create(null));
  
              if (!object.__flags) {
                object.__flags = Object.create(null);
              }
  
              includeAll = arguments.length === 3 ? includeAll : true;
  
              for (var flag in flags) {
                if (
                  includeAll ||
                  (flag !== 'object' && flag !== 'ssfi' && flag !== 'lockSsfi' && flag != 'message')
                ) {
                  object.__flags[flag] = flags[flag];
                }
              }
            };
          },
          {},
        ],
        33: [
          function (require, module, exports) {
            /*!
             * assertion-error
             * Copyright(c) 2013 Jake Luer <jake@qualiancy.com>
             * MIT Licensed
             */
  
            /*!
             * Return a function that will copy properties from
             * one object to another excluding any originally
             * listed. Returned function will create a new `{}`.
             *
             * @param {String} excluded properties ...
             * @return {Function}
             */
  
            function exclude() {
              var excludes = [].slice.call(arguments);
  
              function excludeProps(res, obj) {
                Object.keys(obj).forEach(function (key) {
                  if (!~excludes.indexOf(key)) res[key] = obj[key];
                });
              }
  
              return function extendExclude() {
                var args = [].slice.call(arguments),
                  i = 0,
                  res = {};
  
                for (; i < args.length; i++) {
                  excludeProps(res, args[i]);
                }
  
                return res;
              };
            }
  
            /*!
             * Primary Exports
             */
  
            module.exports = AssertionError;
  
            /**
             * ### AssertionError
             *
             * An extension of the JavaScript `Error` constructor for
             * assertion and validation scenarios.
             *
             * @param {String} message
             * @param {Object} properties to include (optional)
             * @param {callee} start stack function (optional)
             */
  
            function AssertionError(message, _props, ssf) {
              var extend = exclude('name', 'message', 'stack', 'constructor', 'toJSON'),
                props = extend(_props || {});
  
              // default values
              this.message = message || 'Unspecified AssertionError';
              this.showDiff = false;
  
              // copy from properties
              for (var key in props) {
                this[key] = props[key];
              }
  
              // capture stack trace
              ssf = ssf || AssertionError;
              if (Error.captureStackTrace) {
                Error.captureStackTrace(this, ssf);
              } else {
                try {
                  throw new Error();
                } catch (e) {
                  this.stack = e.stack;
                }
              }
            }
  
            /*!
             * Inherit from Error.prototype
             */
  
            AssertionError.prototype = Object.create(Error.prototype);
  
            /*!
             * Statically set name
             */
  
            AssertionError.prototype.name = 'AssertionError';
  
            /*!
             * Ensure correct constructor
             */
  
            AssertionError.prototype.constructor = AssertionError;
  
            /**
             * Allow errors to be converted to JSON for static transfer.
             *
             * @param {Boolean} include stack (default: `true`)
             * @return {Object} object that can be `JSON.stringify`
             */
  
            AssertionError.prototype.toJSON = function (stack) {
              var extend = exclude('constructor', 'toJSON', 'stack'),
                props = extend({ name: this.name }, this);
  
              // include stack if exists and not turned off
              if (false !== stack && this.stack) {
                props.stack = this.stack;
              }
  
              return props;
            };
          },
          {},
        ],
        34: [
          function (require, module, exports) {
            'use strict';
  
            /* !
             * Chai - checkError utility
             * Copyright(c) 2012-2016 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            /**
             * ### .checkError
             *
             * Checks that an error conforms to a given set of criteria and/or retrieves information about it.
             *
             * @api public
             */
  
            /**
             * ### .compatibleInstance(thrown, errorLike)
             *
             * Checks if two instances are compatible (strict equal).
             * Returns false if errorLike is not an instance of Error, because instances
             * can only be compatible if they're both error instances.
             *
             * @name compatibleInstance
             * @param {Error} thrown error
             * @param {Error|ErrorConstructor} errorLike object to compare against
             * @namespace Utils
             * @api public
             */
  
            function compatibleInstance(thrown, errorLike) {
              return errorLike instanceof Error && thrown === errorLike;
            }
  
            /**
             * ### .compatibleConstructor(thrown, errorLike)
             *
             * Checks if two constructors are compatible.
             * This function can receive either an error constructor or
             * an error instance as the `errorLike` argument.
             * Constructors are compatible if they're the same or if one is
             * an instance of another.
             *
             * @name compatibleConstructor
             * @param {Error} thrown error
             * @param {Error|ErrorConstructor} errorLike object to compare against
             * @namespace Utils
             * @api public
             */
  
            function compatibleConstructor(thrown, errorLike) {
              if (errorLike instanceof Error) {
                // If `errorLike` is an instance of any error we compare their constructors
                return (
                  thrown.constructor === errorLike.constructor ||
                  thrown instanceof errorLike.constructor
                );
              } else if (errorLike.prototype instanceof Error || errorLike === Error) {
                // If `errorLike` is a constructor that inherits from Error, we compare `thrown` to `errorLike` directly
                return thrown.constructor === errorLike || thrown instanceof errorLike;
              }
  
              return false;
            }
  
            /**
             * ### .compatibleMessage(thrown, errMatcher)
             *
             * Checks if an error's message is compatible with a matcher (String or RegExp).
             * If the message contains the String or passes the RegExp test,
             * it is considered compatible.
             *
             * @name compatibleMessage
             * @param {Error} thrown error
             * @param {String|RegExp} errMatcher to look for into the message
             * @namespace Utils
             * @api public
             */
  
            function compatibleMessage(thrown, errMatcher) {
              var comparisonString = typeof thrown === 'string' ? thrown : thrown.message;
              if (errMatcher instanceof RegExp) {
                return errMatcher.test(comparisonString);
              } else if (typeof errMatcher === 'string') {
                return comparisonString.indexOf(errMatcher) !== -1; // eslint-disable-line no-magic-numbers
              }
  
              return false;
            }
  
            /**
             * ### .getFunctionName(constructorFn)
             *
             * Returns the name of a function.
             * This also includes a polyfill function if `constructorFn.name` is not defined.
             *
             * @name getFunctionName
             * @param {Function} constructorFn
             * @namespace Utils
             * @api private
             */
  
            var functionNameMatch = /\s*function(?:\s|\s*\/\*[^(?:*\/)]+\*\/\s*)*([^\(\/]+)/;
            function getFunctionName(constructorFn) {
              var name = '';
              if (typeof constructorFn.name === 'undefined') {
                // Here we run a polyfill if constructorFn.name is not defined
                var match = String(constructorFn).match(functionNameMatch);
                if (match) {
                  name = match[1];
                }
              } else {
                name = constructorFn.name;
              }
  
              return name;
            }
  
            /**
             * ### .getConstructorName(errorLike)
             *
             * Gets the constructor name for an Error instance or constructor itself.
             *
             * @name getConstructorName
             * @param {Error|ErrorConstructor} errorLike
             * @namespace Utils
             * @api public
             */
  
            function getConstructorName(errorLike) {
              var constructorName = errorLike;
              if (errorLike instanceof Error) {
                constructorName = getFunctionName(errorLike.constructor);
              } else if (typeof errorLike === 'function') {
                // If `err` is not an instance of Error it is an error constructor itself or another function.
                // If we've got a common function we get its name, otherwise we may need to create a new instance
                // of the error just in case it's a poorly-constructed error. Please see chaijs/chai/issues/45 to know more.
                constructorName =
                  getFunctionName(errorLike).trim() || getFunctionName(new errorLike()); // eslint-disable-line new-cap
              }
  
              return constructorName;
            }
  
            /**
             * ### .getMessage(errorLike)
             *
             * Gets the error message from an error.
             * If `err` is a String itself, we return it.
             * If the error has no message, we return an empty string.
             *
             * @name getMessage
             * @param {Error|String} errorLike
             * @namespace Utils
             * @api public
             */
  
            function getMessage(errorLike) {
              var msg = '';
              if (errorLike && errorLike.message) {
                msg = errorLike.message;
              } else if (typeof errorLike === 'string') {
                msg = errorLike;
              }
  
              return msg;
            }
  
            module.exports = {
              compatibleInstance: compatibleInstance,
              compatibleConstructor: compatibleConstructor,
              compatibleMessage: compatibleMessage,
              getMessage: getMessage,
              getConstructorName: getConstructorName,
            };
          },
          {},
        ],
        35: [
          function (require, module, exports) {
            'use strict';
            /* globals Symbol: false, Uint8Array: false, WeakMap: false */
            /*!
             * deep-eql
             * Copyright(c) 2013 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            var type = require('type-detect');
            function FakeMap() {
              this._key = 'chai/deep-eql__' + Math.random() + Date.now();
            }
  
            FakeMap.prototype = {
              get: function getMap(key) {
                return key[this._key];
              },
              set: function setMap(key, value) {
                if (Object.isExtensible(key)) {
                  Object.defineProperty(key, this._key, {
                    value: value,
                    configurable: true,
                  });
                }
              },
            };
  
            var MemoizeMap = typeof WeakMap === 'function' ? WeakMap : FakeMap;
            /*!
             * Check to see if the MemoizeMap has recorded a result of the two operands
             *
             * @param {Mixed} leftHandOperand
             * @param {Mixed} rightHandOperand
             * @param {MemoizeMap} memoizeMap
             * @returns {Boolean|null} result
             */
            function memoizeCompare(leftHandOperand, rightHandOperand, memoizeMap) {
              // Technically, WeakMap keys can *only* be objects, not primitives.
              if (!memoizeMap || isPrimitive(leftHandOperand) || isPrimitive(rightHandOperand)) {
                return null;
              }
              var leftHandMap = memoizeMap.get(leftHandOperand);
              if (leftHandMap) {
                var result = leftHandMap.get(rightHandOperand);
                if (typeof result === 'boolean') {
                  return result;
                }
              }
              return null;
            }
  
            /*!
             * Set the result of the equality into the MemoizeMap
             *
             * @param {Mixed} leftHandOperand
             * @param {Mixed} rightHandOperand
             * @param {MemoizeMap} memoizeMap
             * @param {Boolean} result
             */
            function memoizeSet(leftHandOperand, rightHandOperand, memoizeMap, result) {
              // Technically, WeakMap keys can *only* be objects, not primitives.
              if (!memoizeMap || isPrimitive(leftHandOperand) || isPrimitive(rightHandOperand)) {
                return;
              }
              var leftHandMap = memoizeMap.get(leftHandOperand);
              if (leftHandMap) {
                leftHandMap.set(rightHandOperand, result);
              } else {
                leftHandMap = new MemoizeMap();
                leftHandMap.set(rightHandOperand, result);
                memoizeMap.set(leftHandOperand, leftHandMap);
              }
            }
  
            /*!
             * Primary Export
             */
  
            module.exports = deepEqual;
            module.exports.MemoizeMap = MemoizeMap;
  
            /**
   * Assert deeply nested sameValue equality between two objects of any type.
   *
   * @param {Mixed} leftHandOperand
   * @param {Mixed} rightHandOperand
   * @param {Object} [options] (optional) Additional options
   * @param {Array} [options.comparator] (optional) Override default algorithm, determining custom equality.
   * @param {Array} [options.memoize] (optional) Provide a custom memoization object which will cache the results of
      complex objects for a speed boost. By passing `false` you can disable memoization, but this will cause circular
      references to blow the stack.
   * @return {Boolean} equal match
   */
            function deepEqual(leftHandOperand, rightHandOperand, options) {
              // If we have a comparator, we can't assume anything; so bail to its check first.
              if (options && options.comparator) {
                return extensiveDeepEqual(leftHandOperand, rightHandOperand, options);
              }
  
              var simpleResult = simpleEqual(leftHandOperand, rightHandOperand);
              if (simpleResult !== null) {
                return simpleResult;
              }
  
              // Deeper comparisons are pushed through to a larger function
              return extensiveDeepEqual(leftHandOperand, rightHandOperand, options);
            }
  
            /**
             * Many comparisons can be canceled out early via simple equality or primitive checks.
             * @param {Mixed} leftHandOperand
             * @param {Mixed} rightHandOperand
             * @return {Boolean|null} equal match
             */
            function simpleEqual(leftHandOperand, rightHandOperand) {
              // Equal references (except for Numbers) can be returned early
              if (leftHandOperand === rightHandOperand) {
                // Handle +-0 cases
                return leftHandOperand !== 0 || 1 / leftHandOperand === 1 / rightHandOperand;
              }
  
              // handle NaN cases
              if (
                leftHandOperand !== leftHandOperand && // eslint-disable-line no-self-compare
                rightHandOperand !== rightHandOperand // eslint-disable-line no-self-compare
              ) {
                return true;
              }
  
              // Anything that is not an 'object', i.e. symbols, functions, booleans, numbers,
              // strings, and undefined, can be compared by reference.
              if (isPrimitive(leftHandOperand) || isPrimitive(rightHandOperand)) {
                // Easy out b/c it would have passed the first equality check
                return false;
              }
              return null;
            }
  
            /*!
   * The main logic of the `deepEqual` function.
   *
   * @param {Mixed} leftHandOperand
   * @param {Mixed} rightHandOperand
   * @param {Object} [options] (optional) Additional options
   * @param {Array} [options.comparator] (optional) Override default algorithm, determining custom equality.
   * @param {Array} [options.memoize] (optional) Provide a custom memoization object which will cache the results of
      complex objects for a speed boost. By passing `false` you can disable memoization, but this will cause circular
      references to blow the stack.
   * @return {Boolean} equal match
  */
            function extensiveDeepEqual(leftHandOperand, rightHandOperand, options) {
              options = options || {};
              options.memoize =
                options.memoize === false ? false : options.memoize || new MemoizeMap();
              var comparator = options && options.comparator;
  
              // Check if a memoized result exists.
              var memoizeResultLeft = memoizeCompare(
                leftHandOperand,
                rightHandOperand,
                options.memoize
              );
              if (memoizeResultLeft !== null) {
                return memoizeResultLeft;
              }
              var memoizeResultRight = memoizeCompare(
                rightHandOperand,
                leftHandOperand,
                options.memoize
              );
              if (memoizeResultRight !== null) {
                return memoizeResultRight;
              }
  
              // If a comparator is present, use it.
              if (comparator) {
                var comparatorResult = comparator(leftHandOperand, rightHandOperand);
                // Comparators may return null, in which case we want to go back to default behavior.
                if (comparatorResult === false || comparatorResult === true) {
                  memoizeSet(leftHandOperand, rightHandOperand, options.memoize, comparatorResult);
                  return comparatorResult;
                }
                // To allow comparators to override *any* behavior, we ran them first. Since it didn't decide
                // what to do, we need to make sure to return the basic tests first before we move on.
                var simpleResult = simpleEqual(leftHandOperand, rightHandOperand);
                if (simpleResult !== null) {
                  // Don't memoize this, it takes longer to set/retrieve than to just compare.
                  return simpleResult;
                }
              }
  
              var leftHandType = type(leftHandOperand);
              if (leftHandType !== type(rightHandOperand)) {
                memoizeSet(leftHandOperand, rightHandOperand, options.memoize, false);
                return false;
              }
  
              // Temporarily set the operands in the memoize object to prevent blowing the stack
              memoizeSet(leftHandOperand, rightHandOperand, options.memoize, true);
  
              var result = extensiveDeepEqualByType(
                leftHandOperand,
                rightHandOperand,
                leftHandType,
                options
              );
              memoizeSet(leftHandOperand, rightHandOperand, options.memoize, result);
              return result;
            }
  
            function extensiveDeepEqualByType(
              leftHandOperand,
              rightHandOperand,
              leftHandType,
              options
            ) {
              switch (leftHandType) {
                case 'String':
                case 'Number':
                case 'Boolean':
                case 'Date':
                  // If these types are their instance types (e.g. `new Number`) then re-deepEqual against their values
                  return deepEqual(leftHandOperand.valueOf(), rightHandOperand.valueOf());
                case 'Promise':
                case 'Symbol':
                case 'function':
                case 'WeakMap':
                case 'WeakSet':
                case 'Error':
                  return leftHandOperand === rightHandOperand;
                case 'Arguments':
                case 'Int8Array':
                case 'Uint8Array':
                case 'Uint8ClampedArray':
                case 'Int16Array':
                case 'Uint16Array':
                case 'Int32Array':
                case 'Uint32Array':
                case 'Float32Array':
                case 'Float64Array':
                case 'Array':
                  return iterableEqual(leftHandOperand, rightHandOperand, options);
                case 'RegExp':
                  return regexpEqual(leftHandOperand, rightHandOperand);
                case 'Generator':
                  return generatorEqual(leftHandOperand, rightHandOperand, options);
                case 'DataView':
                  return iterableEqual(
                    new Uint8Array(leftHandOperand.buffer),
                    new Uint8Array(rightHandOperand.buffer),
                    options
                  );
                case 'ArrayBuffer':
                  return iterableEqual(
                    new Uint8Array(leftHandOperand),
                    new Uint8Array(rightHandOperand),
                    options
                  );
                case 'Set':
                  return entriesEqual(leftHandOperand, rightHandOperand, options);
                case 'Map':
                  return entriesEqual(leftHandOperand, rightHandOperand, options);
                default:
                  return objectEqual(leftHandOperand, rightHandOperand, options);
              }
            }
  
            /*!
             * Compare two Regular Expressions for equality.
             *
             * @param {RegExp} leftHandOperand
             * @param {RegExp} rightHandOperand
             * @return {Boolean} result
             */
  
            function regexpEqual(leftHandOperand, rightHandOperand) {
              return leftHandOperand.toString() === rightHandOperand.toString();
            }
  
            /*!
             * Compare two Sets/Maps for equality. Faster than other equality functions.
             *
             * @param {Set} leftHandOperand
             * @param {Set} rightHandOperand
             * @param {Object} [options] (Optional)
             * @return {Boolean} result
             */
  
            function entriesEqual(leftHandOperand, rightHandOperand, options) {
              // IE11 doesn't support Set#entries or Set#@@iterator, so we need manually populate using Set#forEach
              if (leftHandOperand.size !== rightHandOperand.size) {
                return false;
              }
              if (leftHandOperand.size === 0) {
                return true;
              }
              var leftHandItems = [];
              var rightHandItems = [];
              leftHandOperand.forEach(function gatherEntries(key, value) {
                leftHandItems.push([key, value]);
              });
              rightHandOperand.forEach(function gatherEntries(key, value) {
                rightHandItems.push([key, value]);
              });
              return iterableEqual(leftHandItems.sort(), rightHandItems.sort(), options);
            }
  
            /*!
             * Simple equality for flat iterable objects such as Arrays, TypedArrays or Node.js buffers.
             *
             * @param {Iterable} leftHandOperand
             * @param {Iterable} rightHandOperand
             * @param {Object} [options] (Optional)
             * @return {Boolean} result
             */
  
            function iterableEqual(leftHandOperand, rightHandOperand, options) {
              var length = leftHandOperand.length;
              if (length !== rightHandOperand.length) {
                return false;
              }
              if (length === 0) {
                return true;
              }
              var index = -1;
              while (++index < length) {
                if (deepEqual(leftHandOperand[index], rightHandOperand[index], options) === false) {
                  return false;
                }
              }
              return true;
            }
  
            /*!
             * Simple equality for generator objects such as those returned by generator functions.
             *
             * @param {Iterable} leftHandOperand
             * @param {Iterable} rightHandOperand
             * @param {Object} [options] (Optional)
             * @return {Boolean} result
             */
  
            function generatorEqual(leftHandOperand, rightHandOperand, options) {
              return iterableEqual(
                getGeneratorEntries(leftHandOperand),
                getGeneratorEntries(rightHandOperand),
                options
              );
            }
  
            /*!
             * Determine if the given object has an @@iterator function.
             *
             * @param {Object} target
             * @return {Boolean} `true` if the object has an @@iterator function.
             */
            function hasIteratorFunction(target) {
              return (
                typeof Symbol !== 'undefined' &&
                typeof target === 'object' &&
                typeof Symbol.iterator !== 'undefined' &&
                typeof target[Symbol.iterator] === 'function'
              );
            }
  
            /*!
             * Gets all iterator entries from the given Object. If the Object has no @@iterator function, returns an empty array.
             * This will consume the iterator - which could have side effects depending on the @@iterator implementation.
             *
             * @param {Object} target
             * @returns {Array} an array of entries from the @@iterator function
             */
            function getIteratorEntries(target) {
              if (hasIteratorFunction(target)) {
                try {
                  return getGeneratorEntries(target[Symbol.iterator]());
                } catch (iteratorError) {
                  return [];
                }
              }
              return [];
            }
  
            /*!
             * Gets all entries from a Generator. This will consume the generator - which could have side effects.
             *
             * @param {Generator} target
             * @returns {Array} an array of entries from the Generator.
             */
            function getGeneratorEntries(generator) {
              var generatorResult = generator.next();
              var accumulator = [generatorResult.value];
              while (generatorResult.done === false) {
                generatorResult = generator.next();
                accumulator.push(generatorResult.value);
              }
              return accumulator;
            }
  
            /*!
             * Gets all own and inherited enumerable keys from a target.
             *
             * @param {Object} target
             * @returns {Array} an array of own and inherited enumerable keys from the target.
             */
            function getEnumerableKeys(target) {
              var keys = [];
              for (var key in target) {
                keys.push(key);
              }
              return keys;
            }
  
            /*!
             * Determines if two objects have matching values, given a set of keys. Defers to deepEqual for the equality check of
             * each key. If any value of the given key is not equal, the function will return false (early).
             *
             * @param {Mixed} leftHandOperand
             * @param {Mixed} rightHandOperand
             * @param {Array} keys An array of keys to compare the values of leftHandOperand and rightHandOperand against
             * @param {Object} [options] (Optional)
             * @return {Boolean} result
             */
            function keysEqual(leftHandOperand, rightHandOperand, keys, options) {
              var length = keys.length;
              if (length === 0) {
                return true;
              }
              for (var i = 0; i < length; i += 1) {
                if (
                  deepEqual(leftHandOperand[keys[i]], rightHandOperand[keys[i]], options) === false
                ) {
                  return false;
                }
              }
              return true;
            }
  
            /*!
             * Recursively check the equality of two Objects. Once basic sameness has been established it will defer to `deepEqual`
             * for each enumerable key in the object.
             *
             * @param {Mixed} leftHandOperand
             * @param {Mixed} rightHandOperand
             * @param {Object} [options] (Optional)
             * @return {Boolean} result
             */
  
            function objectEqual(leftHandOperand, rightHandOperand, options) {
              var leftHandKeys = getEnumerableKeys(leftHandOperand);
              var rightHandKeys = getEnumerableKeys(rightHandOperand);
              if (leftHandKeys.length && leftHandKeys.length === rightHandKeys.length) {
                leftHandKeys.sort();
                rightHandKeys.sort();
                if (iterableEqual(leftHandKeys, rightHandKeys) === false) {
                  return false;
                }
                return keysEqual(leftHandOperand, rightHandOperand, leftHandKeys, options);
              }
  
              var leftHandEntries = getIteratorEntries(leftHandOperand);
              var rightHandEntries = getIteratorEntries(rightHandOperand);
              if (leftHandEntries.length && leftHandEntries.length === rightHandEntries.length) {
                leftHandEntries.sort();
                rightHandEntries.sort();
                return iterableEqual(leftHandEntries, rightHandEntries, options);
              }
  
              if (
                leftHandKeys.length === 0 &&
                leftHandEntries.length === 0 &&
                rightHandKeys.length === 0 &&
                rightHandEntries.length === 0
              ) {
                return true;
              }
  
              return false;
            }
  
            /*!
             * Returns true if the argument is a primitive.
             *
             * This intentionally returns true for all objects that can be compared by reference,
             * including functions and symbols.
             *
             * @param {Mixed} value
             * @return {Boolean} result
             */
            function isPrimitive(value) {
              return value === null || typeof value !== 'object';
            }
          },
          { 'type-detect': 38 },
        ],
        36: [
          function (require, module, exports) {
            'use strict';
  
            /* !
             * Chai - getFuncName utility
             * Copyright(c) 2012-2016 Jake Luer <jake@alogicalparadox.com>
             * MIT Licensed
             */
  
            /**
             * ### .getFuncName(constructorFn)
             *
             * Returns the name of a function.
             * When a non-function instance is passed, returns `null`.
             * This also includes a polyfill function if `aFunc.name` is not defined.
             *
             * @name getFuncName
             * @param {Function} funct
             * @namespace Utils
             * @api public
             */
  
            var toString = Function.prototype.toString;
            var functionNameMatch = /\s*function(?:\s|\s*\/\*[^(?:*\/)]+\*\/\s*)*([^\s\(\/]+)/;
            function getFuncName(aFunc) {
              if (typeof aFunc !== 'function') {
                return null;
              }
  
              var name = '';
              if (
                typeof Function.prototype.name === 'undefined' &&
                typeof aFunc.name === 'undefined'
              ) {
                // Here we run a polyfill if Function does not support the `name` property and if aFunc.name is not defined
                var match = toString.call(aFunc).match(functionNameMatch);
                if (match) {
                  name = match[1];
                }
              } else {
                // If we've got a `name` property we just use it
                name = aFunc.name;
              }
  
              return name;
            }
  
            module.exports = getFuncName;
          },
          {},
        ],
        37: [
          function (require, module, exports) {
            'use strict';
  
            /* !
             * Chai - pathval utility
             * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
             * @see https://github.com/logicalparadox/filtr
             * MIT Licensed
             */
  
            /**
             * ### .hasProperty(object, name)
             *
             * This allows checking whether an object has own
             * or inherited from prototype chain named property.
             *
             * Basically does the same thing as the `in`
             * operator but works properly with null/undefined values
             * and other primitives.
             *
             *     var obj = {
             *         arr: ['a', 'b', 'c']
             *       , str: 'Hello'
             *     }
             *
             * The following would be the results.
             *
             *     hasProperty(obj, 'str');  // true
             *     hasProperty(obj, 'constructor');  // true
             *     hasProperty(obj, 'bar');  // false
             *
             *     hasProperty(obj.str, 'length'); // true
             *     hasProperty(obj.str, 1);  // true
             *     hasProperty(obj.str, 5);  // false
             *
             *     hasProperty(obj.arr, 'length');  // true
             *     hasProperty(obj.arr, 2);  // true
             *     hasProperty(obj.arr, 3);  // false
             *
             * @param {Object} object
             * @param {String|Symbol} name
             * @returns {Boolean} whether it exists
             * @namespace Utils
             * @name hasProperty
             * @api public
             */
  
            function hasProperty(obj, name) {
              if (typeof obj === 'undefined' || obj === null) {
                return false;
              }
  
              // The `in` operator does not work with primitives.
              return name in Object(obj);
            }
  
            /* !
             * ## parsePath(path)
             *
             * Helper function used to parse string object
             * paths. Use in conjunction with `internalGetPathValue`.
             *
             *      var parsed = parsePath('myobject.property.subprop');
             *
             * ### Paths:
             *
             * * Can be infinitely deep and nested.
             * * Arrays are also valid using the formal `myobject.document[3].property`.
             * * Literal dots and brackets (not delimiter) must be backslash-escaped.
             *
             * @param {String} path
             * @returns {Object} parsed
             * @api private
             */
  
            function parsePath(path) {
              var str = path.replace(/([^\\])\[/g, '$1.[');
              var parts = str.match(/(\\\.|[^.]+?)+/g);
              return parts.map(function mapMatches(value) {
                var regexp = /^\[(\d+)\]$/;
                var mArr = regexp.exec(value);
                var parsed = null;
                if (mArr) {
                  parsed = { i: parseFloat(mArr[1]) };
                } else {
                  parsed = { p: value.replace(/\\([.\[\]])/g, '$1') };
                }
  
                return parsed;
              });
            }
  
            /* !
             * ## internalGetPathValue(obj, parsed[, pathDepth])
             *
             * Helper companion function for `.parsePath` that returns
             * the value located at the parsed address.
             *
             *      var value = getPathValue(obj, parsed);
             *
             * @param {Object} object to search against
             * @param {Object} parsed definition from `parsePath`.
             * @param {Number} depth (nesting level) of the property we want to retrieve
             * @returns {Object|Undefined} value
             * @api private
             */
  
            function internalGetPathValue(obj, parsed, pathDepth) {
              var temporaryValue = obj;
              var res = null;
              pathDepth = typeof pathDepth === 'undefined' ? parsed.length : pathDepth;
  
              for (var i = 0; i < pathDepth; i++) {
                var part = parsed[i];
                if (temporaryValue) {
                  if (typeof part.p === 'undefined') {
                    temporaryValue = temporaryValue[part.i];
                  } else {
                    temporaryValue = temporaryValue[part.p];
                  }
  
                  if (i === pathDepth - 1) {
                    res = temporaryValue;
                  }
                }
              }
  
              return res;
            }
  
            /* !
             * ## internalSetPathValue(obj, value, parsed)
             *
             * Companion function for `parsePath` that sets
             * the value located at a parsed address.
             *
             *  internalSetPathValue(obj, 'value', parsed);
             *
             * @param {Object} object to search and define on
             * @param {*} value to use upon set
             * @param {Object} parsed definition from `parsePath`
             * @api private
             */
  
            function internalSetPathValue(obj, val, parsed) {
              var tempObj = obj;
              var pathDepth = parsed.length;
              var part = null;
              // Here we iterate through every part of the path
              for (var i = 0; i < pathDepth; i++) {
                var propName = null;
                var propVal = null;
                part = parsed[i];
  
                // If it's the last part of the path, we set the 'propName' value with the property name
                if (i === pathDepth - 1) {
                  propName = typeof part.p === 'undefined' ? part.i : part.p;
                  // Now we set the property with the name held by 'propName' on object with the desired val
                  tempObj[propName] = val;
                } else if (typeof part.p !== 'undefined' && tempObj[part.p]) {
                  tempObj = tempObj[part.p];
                } else if (typeof part.i !== 'undefined' && tempObj[part.i]) {
                  tempObj = tempObj[part.i];
                } else {
                  // If the obj doesn't have the property we create one with that name to define it
                  var next = parsed[i + 1];
                  // Here we set the name of the property which will be defined
                  propName = typeof part.p === 'undefined' ? part.i : part.p;
                  // Here we decide if this property will be an array or a new object
                  propVal = typeof next.p === 'undefined' ? [] : {};
                  tempObj[propName] = propVal;
                  tempObj = tempObj[propName];
                }
              }
            }
  
            /**
             * ### .getPathInfo(object, path)
             *
             * This allows the retrieval of property info in an
             * object given a string path.
             *
             * The path info consists of an object with the
             * following properties:
             *
             * * parent - The parent object of the property referenced by `path`
             * * name - The name of the final property, a number if it was an array indexer
             * * value - The value of the property, if it exists, otherwise `undefined`
             * * exists - Whether the property exists or not
             *
             * @param {Object} object
             * @param {String} path
             * @returns {Object} info
             * @namespace Utils
             * @name getPathInfo
             * @api public
             */
  
            function getPathInfo(obj, path) {
              var parsed = parsePath(path);
              var last = parsed[parsed.length - 1];
              var info = {
                parent:
                  parsed.length > 1 ? internalGetPathValue(obj, parsed, parsed.length - 1) : obj,
                name: last.p || last.i,
                value: internalGetPathValue(obj, parsed),
              };
              info.exists = hasProperty(info.parent, info.name);
  
              return info;
            }
  
            /**
             * ### .getPathValue(object, path)
             *
             * This allows the retrieval of values in an
             * object given a string path.
             *
             *     var obj = {
             *         prop1: {
             *             arr: ['a', 'b', 'c']
             *           , str: 'Hello'
             *         }
             *       , prop2: {
             *             arr: [ { nested: 'Universe' } ]
             *           , str: 'Hello again!'
             *         }
             *     }
             *
             * The following would be the results.
             *
             *     getPathValue(obj, 'prop1.str'); // Hello
             *     getPathValue(obj, 'prop1.att[2]'); // b
             *     getPathValue(obj, 'prop2.arr[0].nested'); // Universe
             *
             * @param {Object} object
             * @param {String} path
             * @returns {Object} value or `undefined`
             * @namespace Utils
             * @name getPathValue
             * @api public
             */
  
            function getPathValue(obj, path) {
              var info = getPathInfo(obj, path);
              return info.value;
            }
  
            /**
             * ### .setPathValue(object, path, value)
             *
             * Define the value in an object at a given string path.
             *
             * ```js
             * var obj = {
             *     prop1: {
             *         arr: ['a', 'b', 'c']
             *       , str: 'Hello'
             *     }
             *   , prop2: {
             *         arr: [ { nested: 'Universe' } ]
             *       , str: 'Hello again!'
             *     }
             * };
             * ```
             *
             * The following would be acceptable.
             *
             * ```js
             * var properties = require('tea-properties');
             * properties.set(obj, 'prop1.str', 'Hello Universe!');
             * properties.set(obj, 'prop1.arr[2]', 'B');
             * properties.set(obj, 'prop2.arr[0].nested.value', { hello: 'universe' });
             * ```
             *
             * @param {Object} object
             * @param {String} path
             * @param {Mixed} value
             * @api private
             */
  
            function setPathValue(obj, path, val) {
              var parsed = parsePath(path);
              internalSetPathValue(obj, val, parsed);
              return obj;
            }
  
            module.exports = {
              hasProperty: hasProperty,
              getPathInfo: getPathInfo,
              getPathValue: getPathValue,
              setPathValue: setPathValue,
            };
          },
          {},
        ],
        38: [
          function (require, module, exports) {
            (function (global, factory) {
              typeof exports === 'object' && typeof module !== 'undefined'
                ? (module.exports = factory())
                : typeof define === 'function' && define.amd
                ? define(factory)
                : (global.typeDetect = factory());
            })(this, function () {
              'use strict';
  
              /* !
               * type-detect
               * Copyright(c) 2013 jake luer <jake@alogicalparadox.com>
               * MIT Licensed
               */
              var promiseExists = typeof Promise === 'function';
  
              /* eslint-disable no-undef */
              var globalObject = typeof self === 'object' ? self : global; // eslint-disable-line id-blacklist
  
              var symbolExists = typeof Symbol !== 'undefined';
              var mapExists = typeof Map !== 'undefined';
              var setExists = typeof Set !== 'undefined';
              var weakMapExists = typeof WeakMap !== 'undefined';
              var weakSetExists = typeof WeakSet !== 'undefined';
              var dataViewExists = typeof DataView !== 'undefined';
              var symbolIteratorExists = symbolExists && typeof Symbol.iterator !== 'undefined';
              var symbolToStringTagExists = symbolExists && typeof Symbol.toStringTag !== 'undefined';
              var setEntriesExists = setExists && typeof Set.prototype.entries === 'function';
              var mapEntriesExists = mapExists && typeof Map.prototype.entries === 'function';
              var setIteratorPrototype =
                setEntriesExists && Object.getPrototypeOf(new Set().entries());
              var mapIteratorPrototype =
                mapEntriesExists && Object.getPrototypeOf(new Map().entries());
              var arrayIteratorExists =
                symbolIteratorExists && typeof Array.prototype[Symbol.iterator] === 'function';
              var arrayIteratorPrototype =
                arrayIteratorExists && Object.getPrototypeOf([][Symbol.iterator]());
              var stringIteratorExists =
                symbolIteratorExists && typeof String.prototype[Symbol.iterator] === 'function';
              var stringIteratorPrototype =
                stringIteratorExists && Object.getPrototypeOf(''[Symbol.iterator]());
              var toStringLeftSliceLength = 8;
              var toStringRightSliceLength = -1;
              /**
               * ### typeOf (obj)
               *
               * Uses `Object.prototype.toString` to determine the type of an object,
               * normalising behaviour across engine versions & well optimised.
               *
               * @param {Mixed} object
               * @return {String} object type
               * @api public
               */
              function typeDetect(obj) {
                /* ! Speed optimisation
                 * Pre:
                 *   string literal     x 3,039,035 ops/sec ±1.62% (78 runs sampled)
                 *   boolean literal    x 1,424,138 ops/sec ±4.54% (75 runs sampled)
                 *   number literal     x 1,653,153 ops/sec ±1.91% (82 runs sampled)
                 *   undefined          x 9,978,660 ops/sec ±1.92% (75 runs sampled)
                 *   function           x 2,556,769 ops/sec ±1.73% (77 runs sampled)
                 * Post:
                 *   string literal     x 38,564,796 ops/sec ±1.15% (79 runs sampled)
                 *   boolean literal    x 31,148,940 ops/sec ±1.10% (79 runs sampled)
                 *   number literal     x 32,679,330 ops/sec ±1.90% (78 runs sampled)
                 *   undefined          x 32,363,368 ops/sec ±1.07% (82 runs sampled)
                 *   function           x 31,296,870 ops/sec ±0.96% (83 runs sampled)
                 */
                var typeofObj = typeof obj;
                if (typeofObj !== 'object') {
                  return typeofObj;
                }
  
                /* ! Speed optimisation
                 * Pre:
                 *   null               x 28,645,765 ops/sec ±1.17% (82 runs sampled)
                 * Post:
                 *   null               x 36,428,962 ops/sec ±1.37% (84 runs sampled)
                 */
                if (obj === null) {
                  return 'null';
                }
  
                /* ! Spec Conformance
                 * Test: `Object.prototype.toString.call(window)``
                 *  - Node === "[object global]"
                 *  - Chrome === "[object global]"
                 *  - Firefox === "[object Window]"
                 *  - PhantomJS === "[object Window]"
                 *  - Safari === "[object Window]"
                 *  - IE 11 === "[object Window]"
                 *  - IE Edge === "[object Window]"
                 * Test: `Object.prototype.toString.call(this)``
                 *  - Chrome Worker === "[object global]"
                 *  - Firefox Worker === "[object DedicatedWorkerGlobalScope]"
                 *  - Safari Worker === "[object DedicatedWorkerGlobalScope]"
                 *  - IE 11 Worker === "[object WorkerGlobalScope]"
                 *  - IE Edge Worker === "[object WorkerGlobalScope]"
                 */
                if (obj === globalObject) {
                  return 'global';
                }
  
                /* ! Speed optimisation
                 * Pre:
                 *   array literal      x 2,888,352 ops/sec ±0.67% (82 runs sampled)
                 * Post:
                 *   array literal      x 22,479,650 ops/sec ±0.96% (81 runs sampled)
                 */
                if (
                  Array.isArray(obj) &&
                  (symbolToStringTagExists === false || !(Symbol.toStringTag in obj))
                ) {
                  return 'Array';
                }
  
                // Not caching existence of `window` and related properties due to potential
                // for `window` to be unset before tests in quasi-browser environments.
                if (typeof window === 'object' && window !== null) {
                  /* ! Spec Conformance
                   * (https://html.spec.whatwg.org/multipage/browsers.html#location)
                   * WhatWG HTML$7.7.3 - The `Location` interface
                   * Test: `Object.prototype.toString.call(window.location)``
                   *  - IE <=11 === "[object Object]"
                   *  - IE Edge <=13 === "[object Object]"
                   */
                  if (typeof window.location === 'object' && obj === window.location) {
                    return 'Location';
                  }
  
                  /* ! Spec Conformance
                   * (https://html.spec.whatwg.org/#document)
                   * WhatWG HTML$3.1.1 - The `Document` object
                   * Note: Most browsers currently adher to the W3C DOM Level 2 spec
                   *       (https://www.w3.org/TR/DOM-Level-2-HTML/html.html#ID-26809268)
                   *       which suggests that browsers should use HTMLTableCellElement for
                   *       both TD and TH elements. WhatWG separates these.
                   *       WhatWG HTML states:
                   *         > For historical reasons, Window objects must also have a
                   *         > writable, configurable, non-enumerable property named
                   *         > HTMLDocument whose value is the Document interface object.
                   * Test: `Object.prototype.toString.call(document)``
                   *  - Chrome === "[object HTMLDocument]"
                   *  - Firefox === "[object HTMLDocument]"
                   *  - Safari === "[object HTMLDocument]"
                   *  - IE <=10 === "[object Document]"
                   *  - IE 11 === "[object HTMLDocument]"
                   *  - IE Edge <=13 === "[object HTMLDocument]"
                   */
                  if (typeof window.document === 'object' && obj === window.document) {
                    return 'Document';
                  }
  
                  if (typeof window.navigator === 'object') {
                    /* ! Spec Conformance
                     * (https://html.spec.whatwg.org/multipage/webappapis.html#mimetypearray)
                     * WhatWG HTML$8.6.1.5 - Plugins - Interface MimeTypeArray
                     * Test: `Object.prototype.toString.call(navigator.mimeTypes)``
                     *  - IE <=10 === "[object MSMimeTypesCollection]"
                     */
                    if (
                      typeof window.navigator.mimeTypes === 'object' &&
                      obj === window.navigator.mimeTypes
                    ) {
                      return 'MimeTypeArray';
                    }
  
                    /* ! Spec Conformance
                     * (https://html.spec.whatwg.org/multipage/webappapis.html#pluginarray)
                     * WhatWG HTML$8.6.1.5 - Plugins - Interface PluginArray
                     * Test: `Object.prototype.toString.call(navigator.plugins)``
                     *  - IE <=10 === "[object MSPluginsCollection]"
                     */
                    if (
                      typeof window.navigator.plugins === 'object' &&
                      obj === window.navigator.plugins
                    ) {
                      return 'PluginArray';
                    }
                  }
  
                  if (
                    (typeof window.HTMLElement === 'function' ||
                      typeof window.HTMLElement === 'object') &&
                    obj instanceof window.HTMLElement
                  ) {
                    /* ! Spec Conformance
                     * (https://html.spec.whatwg.org/multipage/webappapis.html#pluginarray)
                     * WhatWG HTML$4.4.4 - The `blockquote` element - Interface `HTMLQuoteElement`
                     * Test: `Object.prototype.toString.call(document.createElement('blockquote'))``
                     *  - IE <=10 === "[object HTMLBlockElement]"
                     */
                    if (obj.tagName === 'BLOCKQUOTE') {
                      return 'HTMLQuoteElement';
                    }
  
                    /* ! Spec Conformance
                     * (https://html.spec.whatwg.org/#htmltabledatacellelement)
                     * WhatWG HTML$4.9.9 - The `td` element - Interface `HTMLTableDataCellElement`
                     * Note: Most browsers currently adher to the W3C DOM Level 2 spec
                     *       (https://www.w3.org/TR/DOM-Level-2-HTML/html.html#ID-82915075)
                     *       which suggests that browsers should use HTMLTableCellElement for
                     *       both TD and TH elements. WhatWG separates these.
                     * Test: Object.prototype.toString.call(document.createElement('td'))
                     *  - Chrome === "[object HTMLTableCellElement]"
                     *  - Firefox === "[object HTMLTableCellElement]"
                     *  - Safari === "[object HTMLTableCellElement]"
                     */
                    if (obj.tagName === 'TD') {
                      return 'HTMLTableDataCellElement';
                    }
  
                    /* ! Spec Conformance
                     * (https://html.spec.whatwg.org/#htmltableheadercellelement)
                     * WhatWG HTML$4.9.9 - The `td` element - Interface `HTMLTableHeaderCellElement`
                     * Note: Most browsers currently adher to the W3C DOM Level 2 spec
                     *       (https://www.w3.org/TR/DOM-Level-2-HTML/html.html#ID-82915075)
                     *       which suggests that browsers should use HTMLTableCellElement for
                     *       both TD and TH elements. WhatWG separates these.
                     * Test: Object.prototype.toString.call(document.createElement('th'))
                     *  - Chrome === "[object HTMLTableCellElement]"
                     *  - Firefox === "[object HTMLTableCellElement]"
                     *  - Safari === "[object HTMLTableCellElement]"
                     */
                    if (obj.tagName === 'TH') {
                      return 'HTMLTableHeaderCellElement';
                    }
                  }
                }
  
                /* ! Speed optimisation
                 * Pre:
                 *   Float64Array       x 625,644 ops/sec ±1.58% (80 runs sampled)
                 *   Float32Array       x 1,279,852 ops/sec ±2.91% (77 runs sampled)
                 *   Uint32Array        x 1,178,185 ops/sec ±1.95% (83 runs sampled)
                 *   Uint16Array        x 1,008,380 ops/sec ±2.25% (80 runs sampled)
                 *   Uint8Array         x 1,128,040 ops/sec ±2.11% (81 runs sampled)
                 *   Int32Array         x 1,170,119 ops/sec ±2.88% (80 runs sampled)
                 *   Int16Array         x 1,176,348 ops/sec ±5.79% (86 runs sampled)
                 *   Int8Array          x 1,058,707 ops/sec ±4.94% (77 runs sampled)
                 *   Uint8ClampedArray  x 1,110,633 ops/sec ±4.20% (80 runs sampled)
                 * Post:
                 *   Float64Array       x 7,105,671 ops/sec ±13.47% (64 runs sampled)
                 *   Float32Array       x 5,887,912 ops/sec ±1.46% (82 runs sampled)
                 *   Uint32Array        x 6,491,661 ops/sec ±1.76% (79 runs sampled)
                 *   Uint16Array        x 6,559,795 ops/sec ±1.67% (82 runs sampled)
                 *   Uint8Array         x 6,463,966 ops/sec ±1.43% (85 runs sampled)
                 *   Int32Array         x 5,641,841 ops/sec ±3.49% (81 runs sampled)
                 *   Int16Array         x 6,583,511 ops/sec ±1.98% (80 runs sampled)
                 *   Int8Array          x 6,606,078 ops/sec ±1.74% (81 runs sampled)
                 *   Uint8ClampedArray  x 6,602,224 ops/sec ±1.77% (83 runs sampled)
                 */
                var stringTag = symbolToStringTagExists && obj[Symbol.toStringTag];
                if (typeof stringTag === 'string') {
                  return stringTag;
                }
  
                var objPrototype = Object.getPrototypeOf(obj);
                /* ! Speed optimisation
                 * Pre:
                 *   regex literal      x 1,772,385 ops/sec ±1.85% (77 runs sampled)
                 *   regex constructor  x 2,143,634 ops/sec ±2.46% (78 runs sampled)
                 * Post:
                 *   regex literal      x 3,928,009 ops/sec ±0.65% (78 runs sampled)
                 *   regex constructor  x 3,931,108 ops/sec ±0.58% (84 runs sampled)
                 */
                if (objPrototype === RegExp.prototype) {
                  return 'RegExp';
                }
  
                /* ! Speed optimisation
                 * Pre:
                 *   date               x 2,130,074 ops/sec ±4.42% (68 runs sampled)
                 * Post:
                 *   date               x 3,953,779 ops/sec ±1.35% (77 runs sampled)
                 */
                if (objPrototype === Date.prototype) {
                  return 'Date';
                }
  
                /* ! Spec Conformance
                 * (http://www.ecma-international.org/ecma-262/6.0/index.html#sec-promise.prototype-@@tostringtag)
                 * ES6$25.4.5.4 - Promise.prototype[@@toStringTag] should be "Promise":
                 * Test: `Object.prototype.toString.call(Promise.resolve())``
                 *  - Chrome <=47 === "[object Object]"
                 *  - Edge <=20 === "[object Object]"
                 *  - Firefox 29-Latest === "[object Promise]"
                 *  - Safari 7.1-Latest === "[object Promise]"
                 */
                if (promiseExists && objPrototype === Promise.prototype) {
                  return 'Promise';
                }
  
                /* ! Speed optimisation
                 * Pre:
                 *   set                x 2,222,186 ops/sec ±1.31% (82 runs sampled)
                 * Post:
                 *   set                x 4,545,879 ops/sec ±1.13% (83 runs sampled)
                 */
                if (setExists && objPrototype === Set.prototype) {
                  return 'Set';
                }
  
                /* ! Speed optimisation
                 * Pre:
                 *   map                x 2,396,842 ops/sec ±1.59% (81 runs sampled)
                 * Post:
                 *   map                x 4,183,945 ops/sec ±6.59% (82 runs sampled)
                 */
                if (mapExists && objPrototype === Map.prototype) {
                  return 'Map';
                }
  
                /* ! Speed optimisation
                 * Pre:
                 *   weakset            x 1,323,220 ops/sec ±2.17% (76 runs sampled)
                 * Post:
                 *   weakset            x 4,237,510 ops/sec ±2.01% (77 runs sampled)
                 */
                if (weakSetExists && objPrototype === WeakSet.prototype) {
                  return 'WeakSet';
                }
  
                /* ! Speed optimisation
                 * Pre:
                 *   weakmap            x 1,500,260 ops/sec ±2.02% (78 runs sampled)
                 * Post:
                 *   weakmap            x 3,881,384 ops/sec ±1.45% (82 runs sampled)
                 */
                if (weakMapExists && objPrototype === WeakMap.prototype) {
                  return 'WeakMap';
                }
  
                /* ! Spec Conformance
                 * (http://www.ecma-international.org/ecma-262/6.0/index.html#sec-dataview.prototype-@@tostringtag)
                 * ES6$24.2.4.21 - DataView.prototype[@@toStringTag] should be "DataView":
                 * Test: `Object.prototype.toString.call(new DataView(new ArrayBuffer(1)))``
                 *  - Edge <=13 === "[object Object]"
                 */
                if (dataViewExists && objPrototype === DataView.prototype) {
                  return 'DataView';
                }
  
                /* ! Spec Conformance
                 * (http://www.ecma-international.org/ecma-262/6.0/index.html#sec-%mapiteratorprototype%-@@tostringtag)
                 * ES6$23.1.5.2.2 - %MapIteratorPrototype%[@@toStringTag] should be "Map Iterator":
                 * Test: `Object.prototype.toString.call(new Map().entries())``
                 *  - Edge <=13 === "[object Object]"
                 */
                if (mapExists && objPrototype === mapIteratorPrototype) {
                  return 'Map Iterator';
                }
  
                /* ! Spec Conformance
                 * (http://www.ecma-international.org/ecma-262/6.0/index.html#sec-%setiteratorprototype%-@@tostringtag)
                 * ES6$23.2.5.2.2 - %SetIteratorPrototype%[@@toStringTag] should be "Set Iterator":
                 * Test: `Object.prototype.toString.call(new Set().entries())``
                 *  - Edge <=13 === "[object Object]"
                 */
                if (setExists && objPrototype === setIteratorPrototype) {
                  return 'Set Iterator';
                }
  
                /* ! Spec Conformance
                 * (http://www.ecma-international.org/ecma-262/6.0/index.html#sec-%arrayiteratorprototype%-@@tostringtag)
                 * ES6$22.1.5.2.2 - %ArrayIteratorPrototype%[@@toStringTag] should be "Array Iterator":
                 * Test: `Object.prototype.toString.call([][Symbol.iterator]())``
                 *  - Edge <=13 === "[object Object]"
                 */
                if (arrayIteratorExists && objPrototype === arrayIteratorPrototype) {
                  return 'Array Iterator';
                }
  
                /* ! Spec Conformance
                 * (http://www.ecma-international.org/ecma-262/6.0/index.html#sec-%stringiteratorprototype%-@@tostringtag)
                 * ES6$21.1.5.2.2 - %StringIteratorPrototype%[@@toStringTag] should be "String Iterator":
                 * Test: `Object.prototype.toString.call(''[Symbol.iterator]())``
                 *  - Edge <=13 === "[object Object]"
                 */
                if (stringIteratorExists && objPrototype === stringIteratorPrototype) {
                  return 'String Iterator';
                }
  
                /* ! Speed optimisation
                 * Pre:
                 *   object from null   x 2,424,320 ops/sec ±1.67% (76 runs sampled)
                 * Post:
                 *   object from null   x 5,838,000 ops/sec ±0.99% (84 runs sampled)
                 */
                if (objPrototype === null) {
                  return 'Object';
                }
  
                return Object.prototype.toString
                  .call(obj)
                  .slice(toStringLeftSliceLength, toStringRightSliceLength);
              }
  
              return typeDetect;
            });
          },
          {},
        ],
      },
      {},
      [1]
    )(1);
  });
  