text: /*!
   * Vue.js v2.6.11
   * (c) 2014-2020 Evan You
   * Released under the MIT License.
   */
  (function (global, factory) {
    typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory(require('file-loader')) :
    typeof define === 'function' && define.amd ? define(['file-loader'], factory) :
    (global = global || self, global.Vue = factory(global.fileLoader));
  }(this, (function (fileLoader) { 'use strict';
  
    /*  */
  
    var emptyObject = Object.freeze({});
  
    // These helpers produce better VM code in JS engines due to their
    // explicitness and function inlining.
    function isUndef (v) {
      return v === undefined || v === null
    }
  
    function isDef (v) {
      return v !== undefined && v !== null
    }
  
    function isTrue (v) {
      return v === true
    }
  
    function isFalse (v) {
      return v === false
    }
  
    /**
     * Check if value is primitive.
     */
    function isPrimitive (value) {
      return (
        typeof value === 'string' ||
        typeof value === 'number' ||
        // $flow-disable-line
        typeof value === 'symbol' ||
        typeof value === 'boolean'
      )
    }
  
    /**
     * Quick object check - this is primarily used to tell
     * Objects from primitive values when we know the value
     * is a JSON-compliant type.
     */
    function isObject (obj) {
      return obj !== null && typeof obj === 'object'
    }
  
    /**
     * Get the raw type string of a value, e.g., [object Object].
     */
    var _toString = Object.prototype.toString;
  
    function toRawType (value) {
      return _toString.call(value).slice(8, -1)
    }
  
    /**
     * Strict object type check. Only returns true
     * for plain JavaScript objects.
     */
    function isPlainObject (obj) {
      return _toString.call(obj) === '[object Object]'
    }
  
    function isRegExp (v) {
      return _toString.call(v) === '[object RegExp]'
    }
  
    /**
     * Check if val is a valid array index.
     */
    function isValidArrayIndex (val) {
      var n = parseFloat(String(val));
      return n >= 0 && Math.floor(n) === n && isFinite(val)
    }
  
    function isPromise (val) {
      return (
        isDef(val) &&
        typeof val.then === 'function' &&
        typeof val.catch === 'function'
      )
    }
  
    /**
     * Convert a value to a string that is actually rendered.
     */
    function toString (val) {
      return val == null
        ? ''
        : Array.isArray(val) || (isPlainObject(val) && val.toString === _toString)
          ? JSON.stringify(val, null, 2)
          : String(val)
    }
  
    /**
     * Convert an input value to a number for persistence.
     * If the conversion fails, return original string.
     */
    function toNumber (val) {
      var n = parseFloat(val);
      return isNaN(n) ? val : n
    }
  
    /**
     * Make a map and return a function for checking if a key
     * is in that map.
     */
    function makeMap (
      str,
      expectsLowerCase
    ) {
      var map = Object.create(null);
      var list = str.split(',');
      for (var i = 0; i < list.length; i++) {
        map[list[i]] = true;
      }
      return expectsLowerCase
        ? function (val) { return map[val.toLowerCase()]; }
        : function (val) { return map[val]; }
    }
  
    /**
     * Check if a tag is a built-in tag.
     */
    var isBuiltInTag = makeMap('slot,component', true);
  
    /**
     * Check if an attribute is a reserved attribute.
     */
    var isReservedAttribute = makeMap('key,ref,slot,slot-scope,is');
  
    /**
     * Remove an item from an array.
     */
    function remove (arr, item) {
      if (arr.length) {
        var index = arr.indexOf(item);
        if (index > -1) {
          return arr.splice(index, 1)
        }
      }
    }
  
    /**
     * Check whether an object has the property.
     */
    var hasOwnProperty = Object.prototype.hasOwnProperty;
    function hasOwn (obj, key) {
      return hasOwnProperty.call(obj, key)
    }
  
    /**
     * Create a cached version of a pure function.
     */
    function cached (fn) {
      var cache = Object.create(null);
      return (function cachedFn (str) {
        var hit = cache[str];
        return hit || (cache[str] = fn(str))
      })
    }
  
    /**
     * Camelize a hyphen-delimited string.
     */
    var camelizeRE = /-(\w)/g;
    var camelize = cached(function (str) {
      return str.replace(camelizeRE, function (_, c) { return c ? c.toUpperCase() : ''; })
    });
  
    /**
     * Capitalize a string.
     */
    var capitalize = cached(function (str) {
      return str.charAt(0).toUpperCase() + str.slice(1)
    });
  
    /**
     * Hyphenate a camelCase string.
     */
    var hyphenateRE = /\B([A-Z])/g;
    var hyphenate = cached(function (str) {
      return str.replace(hyphenateRE, '-$1').toLowerCase()
    });
  
    /**
     * Simple bind polyfill for environments that do not support it,
     * e.g., PhantomJS 1.x. Technically, we don't need this anymore
     * since native bind is now performant enough in most browsers.
     * But removing it would mean breaking code that was able to run in
     * PhantomJS 1.x, so this must be kept for backward compatibility.
     */
  
    /* istanbul ignore next */
    function polyfillBind (fn, ctx) {
      function boundFn (a) {
        var l = arguments.length;
        return l
          ? l > 1
            ? fn.apply(ctx, arguments)
            : fn.call(ctx, a)
          : fn.call(ctx)
      }
  
      boundFn._length = fn.length;
      return boundFn
    }
  
    function nativeBind (fn, ctx) {
      return fn.bind(ctx)
    }
  
    var bind = Function.prototype.bind
      ? nativeBind
      : polyfillBind;
  
    /**
     * Convert an Array-like object to a real Array.
     */
    function toArray (list, start) {
      start = start || 0;
      var i = list.length - start;
      var ret = new Array(i);
      while (i--) {
        ret[i] = list[i + start];
      }
      return ret
    }
  
    /**
     * Mix properties into target object.
     */
    function extend (to, _from) {
      for (var key in _from) {
        to[key] = _from[key];
      }
      return to
    }
  
    /**
     * Merge an Array of Objects into a single Object.
     */
    function toObject (arr) {
      var res = {};
      for (var i = 0; i < arr.length; i++) {
        if (arr[i]) {
          extend(res, arr[i]);
        }
      }
      return res
    }
  
    /* eslint-disable no-unused-vars */
  
    /**
     * Perform no operation.
     * Stubbing args to make Flow happy without leaving useless transpiled code
     * with ...rest (https://flow.org/blog/2017/05/07/Strict-Function-Call-Arity/).
     */
    function noop (a, b, c) {}
  
    /**
     * Always return false.
     */
    var no = function (a, b, c) { return false; };
  
    /* eslint-enable no-unused-vars */
  
    /**
     * Return the same value.
     */
    var identity = function (_) { return _; };
  
    /**
     * Generate a string containing static keys from compiler modules.
     */
    function genStaticKeys (modules) {
      return modules.reduce(function (keys, m) {
        return keys.concat(m.staticKeys || [])
      }, []).join(',')
    }
  
    /**
     * Check if two values are loosely equal - that is,
     * if they are plain objects, do they have the same shape?
     */
    function looseEqual (a, b) {
      if (a === b) { return true }
      var isObjectA = isObject(a);
      var isObjectB = isObject(b);
      if (isObjectA && isObjectB) {
        try {
          var isArrayA = Array.isArray(a);
          var isArrayB = Array.isArray(b);
          if (isArrayA && isArrayB) {
            return a.length === b.length && a.every(function (e, i) {
              return looseEqual(e, b[i])
            })
          } else if (a instanceof Date && b instanceof Date) {
            return a.getTime() === b.getTime()
          } else if (!isArrayA && !isArrayB) {
            var keysA = Object.keys(a);
            var keysB = Object.keys(b);
            return keysA.length === keysB.length && keysA.every(function (key) {
              return looseEqual(a[key], b[key])
            })
          } else {
            /* istanbul ignore next */
            return false
          }
        } catch (e) {
          /* istanbul ignore next */
          return false
        }
      } else if (!isObjectA && !isObjectB) {
        return String(a) === String(b)
      } else {
        return false
      }
    }
  
    /**
     * Return the first index at which a loosely equal value can be
     * found in the array (if value is a plain object, the array must
     * contain an object of the same shape), or -1 if it is not present.
     */
    function looseIndexOf (arr, val) {
      for (var i = 0; i < arr.length; i++) {
        if (looseEqual(arr[i], val)) { return i }
      }
      return -1
    }
  
    /**
     * Ensure a function is called only once.
     */
    function once (fn) {
      var called = false;
      return function () {
        if (!called) {
          called = true;
          fn.apply(this, arguments);
        }
      }
    }
  
    var SSR_ATTR = 'data-server-rendered';
  
    var ASSET_TYPES = [
      'component',
      'directive',
      'filter'
    ];
  
    var LIFECYCLE_HOOKS = [
      'beforeCreate',
      'created',
      'beforeMount',
      'mounted',
      'beforeUpdate',
      'updated',
      'beforeDestroy',
      'destroyed',
      'activated',
      'deactivated',
      'errorCaptured',
      'serverPrefetch'
    ];
  
    /*  */
  
  
  
    var config = ({
      /**
       * Option merge strategies (used in core/util/options)
       */
      // $flow-disable-line
      optionMergeStrategies: Object.create(null),
  
      /**
       * Whether to suppress warnings.
       */
      silent: false,
  
      /**
       * Show production mode tip message on boot?
       */
      productionTip: "development" !== 'production',
  
      /**
       * Whether to enable devtools
       */
      devtools: "development" !== 'production',
  
      /**
       * Whether to record perf
       */
      performance: false,
  
      /**
       * Error handler for watcher errors
       */
      errorHandler: null,
  
      /**
       * Warn handler for watcher warns
       */
      warnHandler: null,
  
      /**
       * Ignore certain custom elements
       */
      ignoredElements: [],
  
      /**
       * Custom user key aliases for v-on
       */
      // $flow-disable-line
      keyCodes: Object.create(null),
  
      /**
       * Check if a tag is reserved so that it cannot be registered as a
       * component. This is platform-dependent and may be overwritten.
       */
      isReservedTag: no,
  
      /**
       * Check if an attribute is reserved so that it cannot be used as a component
       * prop. This is platform-dependent and may be overwritten.
       */
      isReservedAttr: no,
  
      /**
       * Check if a tag is an unknown element.
       * Platform-dependent.
       */
      isUnknownElement: no,
  
      /**
       * Get the namespace of an element
       */
      getTagNamespace: noop,
  
      /**
       * Parse the real tag name for the specific platform.
       */
      parsePlatformTagName: identity,
  
      /**
       * Check if an attribute must be bound using property, e.g. value
       * Platform-dependent.
       */
      mustUseProp: no,
  
      /**
       * Perform updates asynchronously. Intended to be used by Vue Test Utils
       * This will significantly reduce performance if set to false.
       */
      async: true,
  
      /**
       * Exposed for legacy reasons
       */
      _lifecycleHooks: LIFECYCLE_HOOKS
    });
  
    /*  */
  
    /**
     * unicode letters used for parsing html tags, component names and property paths.
     * using https://www.w3.org/TR/html53/semantics-scripting.html#potentialcustomelementname
     * skipping \u10000-\uEFFFF due to it freezing up PhantomJS
     */
    var unicodeRegExp = /a-zA-Z\u00B7\u00C0-\u00D6\u00D8-\u00F6\u00F8-\u037D\u037F-\u1FFF\u200C-\u200D\u203F-\u2040\u2070-\u218F\u2C00-\u2FEF\u3001-\uD7FF\uF900-\uFDCF\uFDF0-\uFFFD/;
  
    /**
     * Check if a string starts with $ or _
     */
    function isReserved (str) {
      var c = (str + '').charCodeAt(0);
      return c === 0x24 || c === 0x5F
    }
  
    /**
     * Define a property.
     */
    function def (obj, key, val, enumerable) {
      Object.defineProperty(obj, key, {
        value: val,
        enumerable: !!enumerable,
        writable: true,
        configurable: true
      });
    }
  
    /**
     * Parse simple path.
     */
    var bailRE = new RegExp(("[^" + (unicodeRegExp.source) + ".$_\\d]"));
    function parsePath (path) {
      if (bailRE.test(path)) {
        return
      }
      var segments = path.split('.');
      return function (obj) {
        for (var i = 0; i < segments.length; i++) {
          if (!obj) { return }
          obj = obj[segments[i]];
        }
        return obj
      }
    }
  
    /*  */
  
    // can we use __proto__?
    var hasProto = '__proto__' in {};
  
    // Browser environment sniffing
    var inBrowser = typeof window !== 'undefined';
    var inWeex = typeof WXEnvironment !== 'undefined' && !!WXEnvironment.platform;
    var weexPlatform = inWeex && WXEnvironment.platform.toLowerCase();
    var UA = inBrowser && window.navigator.userAgent.toLowerCase();
    var isIE = UA && /msie|trident/.test(UA);
    var isIE9 = UA && UA.indexOf('msie 9.0') > 0;
    var isEdge = UA && UA.indexOf('edge/') > 0;
    var isAndroid = (UA && UA.indexOf('android') > 0) || (weexPlatform === 'android');
    var isIOS = (UA && /iphone|ipad|ipod|ios/.test(UA)) || (weexPlatform === 'ios');
    var isChrome = UA && /chrome\/\d+/.test(UA) && !isEdge;
    var isPhantomJS = UA && /phantomjs/.test(UA);
    var isFF = UA && UA.match(/firefox\/(\d+)/);
  
    // Firefox has a "watch" function on Object.prototype...
    var nativeWatch = ({}).watch;
  
    var supportsPassive = false;
    if (inBrowser) {
      try {
        var opts = {};
        Object.defineProperty(opts, 'passive', ({
          get: function get () {
            /* istanbul ignore next */
            supportsPassive = true;
          }
        })); // https://github.com/facebook/flow/issues/285
        window.addEventListener('test-passive', null, opts);
      } catch (e) {}
    }
  
    // this needs to be lazy-evaled because vue may be required before
    // vue-server-renderer can set VUE_ENV
    var _isServer;
    var isServerRendering = function () {
      if (_isServer === undefined) {
        /* istanbul ignore if */
        if (!inBrowser && !inWeex && typeof global !== 'undefined') {
          // detect presence of vue-server-renderer and avoid
          // Webpack shimming the process
          _isServer = global['process'] && global['process'].env.VUE_ENV === 'server';
        } else {
          _isServer = false;
        }
      }
      return _isServer
    };
  
    // detect devtools
    var devtools = inBrowser && window.__VUE_DEVTOOLS_GLOBAL_HOOK__;
  
    /* istanbul ignore next */
    function isNative (Ctor) {
      return typeof Ctor === 'function' && /native code/.test(Ctor.toString())
    }
  
    var hasSymbol =
      typeof Symbol !== 'undefined' && isNative(Symbol) &&
      typeof Reflect !== 'undefined' && isNative(Reflect.ownKeys);
  
    var _Set;
    /* istanbul ignore if */ // $flow-disable-line
    if (typeof Set !== 'undefined' && isNative(Set)) {
      // use native Set when available.
      _Set = Set;
    } else {
      // a non-standard Set polyfill that only works with primitive keys.
      _Set = /*@__PURE__*/(function () {
        function Set () {
          this.set = Object.create(null);
        }
        Set.prototype.has = function has (key) {
          return this.set[key] === true
        };
        Set.prototype.add = function add (key) {
          this.set[key] = true;
        };
        Set.prototype.clear = function clear () {
          this.set = Object.create(null);
        };
  
        return Set;
      }());
    }
  
    /*  */
  
    var warn = noop;
    var tip = noop;
    var generateComponentTrace = (noop); // work around flow check
    var formatComponentName = (noop);
  
    {
      var hasConsole = typeof console !== 'undefined';
      var classifyRE = /(?:^|[-_])(\w)/g;
      var classify = function (str) { return str
        .replace(classifyRE, function (c) { return c.toUpperCase(); })
        .replace(/[-_]/g, ''); };
  
      warn = function (msg, vm) {
        var trace = vm ? generateComponentTrace(vm) : '';
  
        if (config.warnHandler) {
          config.warnHandler.call(null, msg, vm, trace);
        } else if (hasConsole && (!config.silent)) {
          console.error(("[Vue warn]: " + msg + trace));
        }
      };
  
      tip = function (msg, vm) {
        if (hasConsole && (!config.silent)) {
          console.warn("[Vue tip]: " + msg + (
            vm ? generateComponentTrace(vm) : ''
          ));
        }
      };
  
      formatComponentName = function (vm, includeFile) {
        if (vm.$root === vm) {
          return '<Root>'
        }
        var options = typeof vm === 'function' && vm.cid != null
          ? vm.options
          : vm._isVue
            ? vm.$options || vm.constructor.options
            : vm;
        var name = options.name || options._componentTag;
        var file = options.__file;
        if (!name && file) {
          var match = file.match(/([^/\\]+)\.vue$/);
          name = match && match[1];
        }
  
        return (
          (name ? ("<" + (classify(name)) + ">") : "<Anonymous>") +
          (file && includeFile !== false ? (" at " + file) : '')
        )
      };
  
      var repeat = function (str, n) {
        var res = '';
        while (n) {
          if (n % 2 === 1) { res += str; }
          if (n > 1) { str += str; }
          n >>= 1;
        }
        return res
      };
  
      generateComponentTrace = function (vm) {
        if (vm._isVue && vm.$parent) {
          var tree = [];
          var currentRecursiveSequence = 0;
          while (vm) {
            if (tree.length > 0) {
              var last = tree[tree.length - 1];
              if (last.constructor === vm.constructor) {
                currentRecursiveSequence++;
                vm = vm.$parent;
                continue
              } else if (currentRecursiveSequence > 0) {
                tree[tree.length - 1] = [last, currentRecursiveSequence];
                currentRecursiveSequence = 0;
              }
            }
            tree.push(vm);
            vm = vm.$parent;
          }
          return '\n\nfound in\n\n' + tree
            .map(function (vm, i) { return ("" + (i === 0 ? '---> ' : repeat(' ', 5 + i * 2)) + (Array.isArray(vm)
                ? ((formatComponentName(vm[0])) + "... (" + (vm[1]) + " recursive calls)")
                : formatComponentName(vm))); })
            .join('\n')
        } else {
          return ("\n\n(found in " + (formatComponentName(vm)) + ")")
        }
      };
    }
  
    /*  */
  
    var uid = 0;
  
    /**
     * A dep is an observable that can have multiple
     * directives subscribing to it.
     */
    var Dep = function Dep() {
      this.id = uid++;
      this.subs = [];
    };
  
    Dep.prototype.addSub = function addSub (sub) {
      this.subs.push(sub);
    };
  
    Dep.prototype.removeSub = function removeSub (sub) {
      remove(this.subs, sub);
    };
  
    Dep.prototype.depend = function depend () {
      if (Dep.target) {
        Dep.target.addDep(this);
      }
    };
  
    Dep.prototype.notify = function notify () {
      // stabilize the subscriber list first
      var subs = this.subs.slice();
      if ( !config.async) {
        // subs aren't sorted in scheduler if not running async
        // we need to sort them now to make sure they fire in correct
        // order
        subs.sort(function (a, b) { return a.id - b.id; });
      }
      for (var i = 0, l = subs.length; i < l; i++) {
        // watcher update
        subs[i].update();
      }
    };
  
    // The current target watcher being evaluated.
    // This is globally unique because only one watcher
    // can be evaluated at a time.
    Dep.target = null;
    var targetStack = [];
  
    function pushTarget(target) {
      targetStack.push(target);
      Dep.target = target;
    }
  
    function popTarget() {
      targetStack.pop();
      Dep.target = targetStack[targetStack.length - 1];
    }
  
    /*  */
  
    var VNode = function VNode (
      tag,
      data,
      children,
      text,
      elm,
      context,
      componentOptions,
      asyncFactory
    ) {
      this.tag = tag;
      this.data = data;
      this.children = children;
      this.text = text;
      this.elm = elm;
      this.ns = undefined;
      this.context = context;
      this.fnContext = undefined;
      this.fnOptions = undefined;
      this.fnScopeId = undefined;
      this.key = data && data.key;
      this.componentOptions = componentOptions;
      this.componentInstance = undefined;
      this.parent = undefined;
      this.raw = false;
      this.isStatic = false;
      this.isRootInsert = true;
      this.isComment = false;
      this.isCloned = false;
      this.isOnce = false;
      this.asyncFactory = asyncFactory;
      this.asyncMeta = undefined;
      this.isAsyncPlaceholder = false;
    };
  
    var prototypeAccessors = { child: { configurable: true } };
  
    // DEPRECATED: alias for componentInstance for backwards compat.
    /* istanbul ignore next */
    prototypeAccessors.child.get = function () {
      return this.componentInstance
    };
  
    Object.defineProperties( VNode.prototype, prototypeAccessors );
  
    var createEmptyVNode = function (text) {
      if ( text === void 0 ) text = '';
  
      var node = new VNode();
      node.text = text;
      node.isComment = true;
      return node
    };
  
    function createTextVNode (val) {
      return new VNode(undefined, undefined, undefined, String(val))
    }
  
    // optimized shallow clone
    // used for static nodes and slot nodes because they may be reused across
    // multiple renders, cloning them avoids errors when DOM manipulations rely
    // on their elm reference.
    function cloneVNode (vnode) {
      var cloned = new VNode(
        vnode.tag,
        vnode.data,
        // #7975
        // clone children array to avoid mutating original in case of cloning
        // a child.
        vnode.children && vnode.children.slice(),
        vnode.text,
        vnode.elm,
        vnode.context,
        vnode.componentOptions,
        vnode.asyncFactory
      );
      cloned.ns = vnode.ns;
      cloned.isStatic = vnode.isStatic;
      cloned.key = vnode.key;
      cloned.isComment = vnode.isComment;
      cloned.fnContext = vnode.fnContext;
      cloned.fnOptions = vnode.fnOptions;
      cloned.fnScopeId = vnode.fnScopeId;
      cloned.asyncMeta = vnode.asyncMeta;
      cloned.isCloned = true;
      return cloned
    }
  
    /*
     * not type checking this file because flow doesn't play well with
     * dynamically accessing methods on Array prototype
     */
  
    var arrayProto = Array.prototype;
    var arrayMethods = Object.create(arrayProto);
  
    var methodsToPatch = [
      'push',
      'pop',
      'shift',
      'unshift',
      'splice',
      'sort',
      'reverse'
    ];
  
    /**
     * Intercept mutating methods and emit events
     */
    methodsToPatch.forEach(function (method) {
      // cache original method
      var original = arrayProto[method];
      def(arrayMethods, method, function mutator () {
        var args = [], len = arguments.length;
        while ( len-- ) args[ len ] = arguments[ len ];
  
        var result = original.apply(this, args);
        var ob = this.__ob__;
        var inserted;
        switch (method) {
          case 'push':
          case 'unshift':
            inserted = args;
            break
          case 'splice':
            inserted = args.slice(2);
            break
        }
        if (inserted) { ob.observeArray(inserted); }
        // notify change
        ob.dep.notify();
        return result
      });
    });
  
    /*  */
  
    var arrayKeys = Object.getOwnPropertyNames(arrayMethods);
  
    /**
     * In some cases we may want to disable observation inside a component's
     * update computation.
     */
    var shouldObserve = true;
  
    function toggleObserving (value) {
      shouldObserve = value;
    }
  
    /**
     * Observer class that is attached to each observed
     * object. Once attached, the observer converts the target
     * object's property keys into getter/setters that
     * collect dependencies and dispatch updates.
     */
    var Observer = function Observer (value) {
      this.value = value;
      this.dep = new Dep();
      this.vmCount = 0;
      def(value, '__ob__', this);
      if (Array.isArray(value)) {
        if (hasProto) {
          protoAugment(value, arrayMethods);
        } else {
          copyAugment(value, arrayMethods, arrayKeys);
        }
        this.observeArray(value);
      } else {
        this.walk(value);
      }
    };
  
    /**
     * Walk through all properties and convert them into
     * getter/setters. This method should only be called when
     * value type is Object.
     */
    Observer.prototype.walk = function walk (obj) {
      var keys = Object.keys(obj);
      for (var i = 0; i < keys.length; i++) {
        defineReactive(obj, keys[i]);
      }
    };
  
    /**
     * Observe a list of Array items.
     */
    Observer.prototype.observeArray = function observeArray (items) {
      for (var i = 0, l = items.length; i < l; i++) {
        observe(items[i]);
      }
    };
  
    // helpers
  
    /**
     * Augment a target Object or Array by intercepting
     * the prototype chain using __proto__
     */
    function protoAugment (target, src) {
      /* eslint-disable no-proto */
      target.__proto__ = src;
      /* eslint-enable no-proto */
    }
  
    /**
     * Augment a target Object or Array by defining
     * hidden properties.
     */
    /* istanbul ignore next */
    function copyAugment (target, src, keys) {
      for (var i = 0, l = keys.length; i < l; i++) {
        var key = keys[i];
        def(target, key, src[key]);
      }
    }
  
    /**
     * Attempt to create an observer instance for a value,
     * returns the new observer if successfully observed,
     * or the existing observer if the value already has one.
     */
    function observe (value, asRootData) {
      if (!isObject(value) || value instanceof VNode) {
        return
      }
      var ob;
      if (hasOwn(value, '__ob__') && value.__ob__ instanceof Observer) {
        ob = value.__ob__;
      } else if (
        shouldObserve &&
        !isServerRendering() &&
        (Array.isArray(value) || isPlainObject(value)) &&
        Object.isExtensible(value) &&
        !value._isVue
      ) {
        ob = new Observer(value);
      }
      if (asRootData && ob) {
        ob.vmCount++;
      }
      return ob
    }
  
    /**
     * Define a reactive property on an Object.
     */
    function defineReactive (
      obj,
      key,
      val,
      customSetter,
      shallow
    ) {
      var dep = new Dep();
  
      var property = Object.getOwnPropertyDescriptor(obj, key);
      if (property && property.configurable === false) {
        return
      }
  
      // cater for pre-defined getter/setters
      var getter = property && property.get;
      var setter = property && property.set;
      if ((!getter || setter) && arguments.length === 2) {
        val = obj[key];
      }
  
      var childOb = !shallow && observe(val);
      Object.defineProperty(obj, key, {
        enumerable: true,
        configurable: true,
        get: function reactiveGetter () {
          var value = getter ? getter.call(obj) : val;
          if (Dep.target) {
            dep.depend();
            if (childOb) {
              childOb.dep.depend();
              if (Array.isArray(value)) {
                dependArray(value);
              }
            }
          }
          return value
        },
        set: function reactiveSetter (newVal) {
          var value = getter ? getter.call(obj) : val;
          /* eslint-disable no-self-compare */
          if (newVal === value || (newVal !== newVal && value !== value)) {
            return
          }
          /* eslint-enable no-self-compare */
          if ( customSetter) {
            customSetter();
          }
          // #7981: for accessor properties without setter
          if (getter && !setter) { return }
          if (setter) {
            setter.call(obj, newVal);
          } else {
            val = newVal;
          }
          childOb = !shallow && observe(newVal);
          dep.notify();
        }
      });
    }
  
    /**
     * Set a property on an object. Adds the new property and
     * triggers change notification if the property doesn't
     * already exist.
     */
    function set (target, key, val) {
      if (
        (isUndef(target) || isPrimitive(target))
      ) {
        warn(("Cannot set reactive property on undefined, null, or primitive value: " + ((target))));
      }
      if (Array.isArray(target) && isValidArrayIndex(key)) {
        target.length = Math.max(target.length, key);
        target.splice(key, 1, val);
        return val
      }
      if (key in target && !(key in Object.prototype)) {
        target[key] = val;
        return val
      }
      var ob = (target).__ob__;
      if (target._isVue || (ob && ob.vmCount)) {
         warn(
          'Avoid adding reactive properties to a Vue instance or its root $data ' +
          'at runtime - declare it upfront in the data option.'
        );
        return val
      }
      if (!ob) {
        target[key] = val;
        return val
      }
      defineReactive(ob.value, key, val);
      ob.dep.notify();
      return val
    }
  
    /**
     * Delete a property and trigger change if necessary.
     */
    function del (target, key) {
      if (
        (isUndef(target) || isPrimitive(target))
      ) {
        warn(("Cannot delete reactive property on undefined, null, or primitive value: " + ((target))));
      }
      if (Array.isArray(target) && isValidArrayIndex(key)) {
        target.splice(key, 1);
        return
      }
      var ob = (target).__ob__;
      if (target._isVue || (ob && ob.vmCount)) {
         warn(
          'Avoid deleting properties on a Vue instance or its root $data ' +
          '- just set it to null.'
        );
        return
      }
      if (!hasOwn(target, key)) {
        return
      }
      delete target[key];
      if (!ob) {
        return
      }
      ob.dep.notify();
    }
  
    /**
     * Collect dependencies on array elements when the array is touched, since
     * we cannot intercept array element access like property getters.
     */
    function dependArray (value) {
      for (var e = (void 0), i = 0, l = value.length; i < l; i++) {
        e = value[i];
        e && e.__ob__ && e.__ob__.dep.depend();
        if (Array.isArray(e)) {
          dependArray(e);
        }
      }
    }
  
    /*  */
  
    /**
     * Option overwriting strategies are functions that handle
     * how to merge a parent option value and a child option
     * value into the final value.
     */
    var strats = config.optionMergeStrategies;
  
    /**
     * Options with restrictions
     */
    {
      strats.el = strats.propsData = function (parent, child, vm, key) {
        if (!vm) {
          warn(
            "option \"" + key + "\" can only be used during instance " +
            'creation with the `new` keyword.'
          );
        }
        return defaultStrat(parent, child)
      };
    }
  
    /**
     * Helper that recursively merges two data objects together.
     */
    function mergeData (to, from) {
      if (!from) { return to }
      var key, toVal, fromVal;
  
      var keys = hasSymbol
        ? Reflect.ownKeys(from)
        : Object.keys(from);
  
      for (var i = 0; i < keys.length; i++) {
        key = keys[i];
        // in case the object is already observed...
        if (key === '__ob__') { continue }
        toVal = to[key];
        fromVal = from[key];
        if (!hasOwn(to, key)) {
          set(to, key, fromVal);
        } else if (
          toVal !== fromVal &&
          isPlainObject(toVal) &&
          isPlainObject(fromVal)
        ) {
          mergeData(toVal, fromVal);
        }
      }
      return to
    }
  
    /**
     * Data
     */
    function mergeDataOrFn (
      parentVal,
      childVal,
      vm
    ) {
      if (!vm) {
        // in a Vue.extend merge, both should be functions
        if (!childVal) {
          return parentVal
        }
        if (!parentVal) {
          return childVal
        }
        // when parentVal & childVal are both present,
        // we need to return a function that returns the
        // merged result of both functions... no need to
        // check if parentVal is a function here because
        // it has to be a function to pass previous merges.
        return function mergedDataFn () {
          return mergeData(
            typeof childVal === 'function' ? childVal.call(this, this) : childVal,
            typeof parentVal === 'function' ? parentVal.call(this, this) : parentVal
          )
        }
      } else {
        return function mergedInstanceDataFn () {
          // instance merge
          var instanceData = typeof childVal === 'function'
            ? childVal.call(vm, vm)
            : childVal;
          var defaultData = typeof parentVal === 'function'
            ? parentVal.call(vm, vm)
            : parentVal;
          if (instanceData) {
            return mergeData(instanceData, defaultData)
          } else {
            return defaultData
          }
        }
      }
    }
  
    strats.data = function (
      parentVal,
      childVal,
      vm
    ) {
      if (!vm) {
        if (childVal && typeof childVal !== 'function') {
           warn(
            'The "data" option should be a function ' +
            'that returns a per-instance value in component ' +
            'definitions.',
            vm
          );
  
          return parentVal
        }
        return mergeDataOrFn(parentVal, childVal)
      }
  
      return mergeDataOrFn(parentVal, childVal, vm)
    };
  
    /**
     * Hooks and props are merged as arrays.
     */
    function mergeHook (
      parentVal,
      childVal
    ) {
      var res = childVal
        ? parentVal
          ? parentVal.concat(childVal)
          : Array.isArray(childVal)
            ? childVal
            : [childVal]
        : parentVal;
      return res
        ? dedupeHooks(res)
        : res
    }
  
    function dedupeHooks (hooks) {
      var res = [];
      for (var i = 0; i < hooks.length; i++) {
        if (res.indexOf(hooks[i]) === -1) {
          res.push(hooks[i]);
        }
      }
      return res
    }
  
    LIFECYCLE_HOOKS.forEach(function (hook) {
      strats[hook] = mergeHook;
    });
  
    /**
     * Assets
     *
     * When a vm is present (instance creation), we need to do
     * a three-way merge between constructor options, instance
     * options and parent options.
     */
    function mergeAssets (
      parentVal,
      childVal,
      vm,
      key
    ) {
      var res = Object.create(parentVal || null);
      if (childVal) {
         assertObjectType(key, childVal, vm);
        return extend(res, childVal)
      } else {
        return res
      }
    }
  
    ASSET_TYPES.forEach(function (type) {
      strats[type + 's'] = mergeAssets;
    });
  
    /**
     * Watchers.
     *
     * Watchers hashes should not overwrite one
     * another, so we merge them as arrays.
     */
    strats.watch = function (
      parentVal,
      childVal,
      vm,
      key
    ) {
      // work around Firefox's Object.prototype.watch...
      if (parentVal === nativeWatch) { parentVal = undefined; }
      if (childVal === nativeWatch) { childVal = undefined; }
      /* istanbul ignore if */
      if (!childVal) { return Object.create(parentVal || null) }
      {
        assertObjectType(key, childVal, vm);
      }
      if (!parentVal) { return childVal }
      var ret = {};
      extend(ret, parentVal);
      for (var key$1 in childVal) {
        var parent = ret[key$1];
        var child = childVal[key$1];
        if (parent && !Array.isArray(parent)) {
          parent = [parent];
        }
        ret[key$1] = parent
          ? parent.concat(child)
          : Array.isArray(child) ? child : [child];
      }
      return ret
    };
  
    /**
     * Other object hashes.
     */
    strats.props =
    strats.methods =
    strats.inject =
    strats.computed = function (
      parentVal,
      childVal,
      vm,
      key
    ) {
      if (childVal && "development" !== 'production') {
        assertObjectType(key, childVal, vm);
      }
      if (!parentVal) { return childVal }
      var ret = Object.create(null);
      extend(ret, parentVal);
      if (childVal) { extend(ret, childVal); }
      return ret
    };
    strats.provide = mergeDataOrFn;
  
    /**
     * Default strategy.
     */
    var defaultStrat = function (parentVal, childVal) {
      return childVal === undefined
        ? parentVal
        : childVal
    };
  
    /**
     * Validate component names
     */
    function checkComponents (options) {
      for (var key in options.components) {
        validateComponentName(key);
      }
    }
  
    function validateComponentName (name) {
      if (!new RegExp(("^[a-zA-Z][\\-\\.0-9_" + (unicodeRegExp.source) + "]*$")).test(name)) {
        warn(
          'Invalid component name: "' + name + '". Component names ' +
          'should conform to valid custom element name in html5 specification.'
        );
      }
      if (isBuiltInTag(name) || config.isReservedTag(name)) {
        warn(
          'Do not use built-in or reserved HTML elements as component ' +
          'id: ' + name
        );
      }
    }
  
    /**
     * Ensure all props option syntax are normalized into the
     * Object-based format.
     */
    function normalizeProps (options, vm) {
      var props = options.props;
      if (!props) { return }
      var res = {};
      var i, val, name;
      if (Array.isArray(props)) {
        i = props.length;
        while (i--) {
          val = props[i];
          if (typeof val === 'string') {
            name = camelize(val);
            res[name] = { type: null };
          } else {
            warn('props must be strings when using array syntax.');
          }
        }
      } else if (isPlainObject(props)) {
        for (var key in props) {
          val = props[key];
          name = camelize(key);
          res[name] = isPlainObject(val)
            ? val
            : { type: val };
        }
      } else {
        warn(
          "Invalid value for option \"props\": expected an Array or an Object, " +
          "but got " + (toRawType(props)) + ".",
          vm
        );
      }
      options.props = res;
    }
  
    /**
     * Normalize all injections into Object-based format
     */
    function normalizeInject (options, vm) {
      var inject = options.inject;
      if (!inject) { return }
      var normalized = options.inject = {};
      if (Array.isArray(inject)) {
        for (var i = 0; i < inject.length; i++) {
          normalized[inject[i]] = { from: inject[i] };
        }
      } else if (isPlainObject(inject)) {
        for (var key in inject) {
          var val = inject[key];
          normalized[key] = isPlainObject(val)
            ? extend({ from: key }, val)
            : { from: val };
        }
      } else {
        warn(
          "Invalid value for option \"inject\": expected an Array or an Object, " +
          "but got " + (toRawType(inject)) + ".",
          vm
        );
      }
    }
  
    /**
     * Normalize raw function directives into object format.
     */
    function normalizeDirectives (options) {
      var dirs = options.directives;
      if (dirs) {
        for (var key in dirs) {
          var def = dirs[key];
          if (typeof def === 'function') {
            dirs[key] = { bind: def, update: def };
          }
        }
      }
    }
  
    function assertObjectType (name, value, vm) {
      if (!isPlainObject(value)) {
        warn(
          "Invalid value for option \"" + name + "\": expected an Object, " +
          "but got " + (toRawType(value)) + ".",
          vm
        );
      }
    }
  
    /**
     * Merge two option objects into a new one.
     * Core utility used in both instantiation and inheritance.
     */
    function mergeOptions (
      parent,
      child,
      vm
    ) {
      {
        checkComponents(child);
      }
  
      if (typeof child === 'function') {
        child = child.options;
      }
  
      normalizeProps(child, vm);
      normalizeInject(child, vm);
      normalizeDirectives(child);
  
      // Apply extends and mixins on the child options,
      // but only if it is a raw options object that isn't
      // the result of another mergeOptions call.
      // Only merged options has the _base property.
      if (!child._base) {
        if (child.extends) {
          parent = mergeOptions(parent, child.extends, vm);
        }
        if (child.mixins) {
          for (var i = 0, l = child.mixins.length; i < l; i++) {
            parent = mergeOptions(parent, child.mixins[i], vm);
          }
        }
      }
  
      var options = {};
      var key;
      for (key in parent) {
        mergeField(key);
      }
      for (key in child) {
        if (!hasOwn(parent, key)) {
          mergeField(key);
        }
      }
      function mergeField (key) {
        var strat = strats[key] || defaultStrat;
        options[key] = strat(parent[key], child[key], vm, key);
      }
      return options
    }
  
    /**
     * Resolve an asset.
     * This function is used because child instances need access
     * to assets defined in its ancestor chain.
     */
    function resolveAsset (
      options,
      type,
      id,
      warnMissing
    ) {
      /* istanbul ignore if */
      if (typeof id !== 'string') {
        return
      }
      var assets = options[type];
      // check local registration variations first
      if (hasOwn(assets, id)) { return assets[id] }
      var camelizedId = camelize(id);
      if (hasOwn(assets, camelizedId)) { return assets[camelizedId] }
      var PascalCaseId = capitalize(camelizedId);
      if (hasOwn(assets, PascalCaseId)) { return assets[PascalCaseId] }
      // fallback to prototype chain
      var res = assets[id] || assets[camelizedId] || assets[PascalCaseId];
      if ( warnMissing && !res) {
        warn(
          'Failed to resolve ' + type.slice(0, -1) + ': ' + id,
          options
        );
      }
      return res
    }
  
    /*  */
  
  
  
    function validateProp (
      key,
      propOptions,
      propsData,
      vm
    ) {
      var prop = propOptions[key];
      var absent = !hasOwn(propsData, key);
      var value = propsData[key];
      // boolean casting
      var booleanIndex = getTypeIndex(Boolean, prop.type);
      if (booleanIndex > -1) {
        if (absent && !hasOwn(prop, 'default')) {
          value = false;
        } else if (value === '' || value === hyphenate(key)) {
          // only cast empty string / same name to boolean if
          // boolean has higher priority
          var stringIndex = getTypeIndex(String, prop.type);
          if (stringIndex < 0 || booleanIndex < stringIndex) {
            value = true;
          }
        }
      }
      // check default value
      if (value === undefined) {
        value = getPropDefaultValue(vm, prop, key);
        // since the default value is a fresh copy,
        // make sure to observe it.
        var prevShouldObserve = shouldObserve;
        toggleObserving(true);
        observe(value);
        toggleObserving(prevShouldObserve);
      }
      {
        assertProp(prop, key, value, vm, absent);
      }
      return value
    }
  
    /**
     * Get the default value of a prop.
     */
    function getPropDefaultValue (vm, prop, key) {
      // no default, return undefined
      if (!hasOwn(prop, 'default')) {
        return undefined
      }
      var def = prop.default;
      // warn against non-factory defaults for Object & Array
      if ( isObject(def)) {
        warn(
          'Invalid default value for prop "' + key + '": ' +
          'Props with type Object/Array must use a factory function ' +
          'to return the default value.',
          vm
        );
      }
      // the raw prop value was also undefined from previous render,
      // return previous default value to avoid unnecessary watcher trigger
      if (vm && vm.$options.propsData &&
        vm.$options.propsData[key] === undefined &&
        vm._props[key] !== undefined
      ) {
        return vm._props[key]
      }
      // call factory function for non-Function types
      // a value is Function if its prototype is function even across different execution context
      return typeof def === 'function' && getType(prop.type) !== 'Function'
        ? def.call(vm)
        : def
    }
  
    /**
     * Assert whether a prop is valid.
     */
    function assertProp (
      prop,
      name,
      value,
      vm,
      absent
    ) {
      if (prop.required && absent) {
        warn(
          'Missing required prop: "' + name + '"',
          vm
        );
        return
      }
      if (value == null && !prop.required) {
        return
      }
      var type = prop.type;
      var valid = !type || type === true;
      var expectedTypes = [];
      if (type) {
        if (!Array.isArray(type)) {
          type = [type];
        }
        for (var i = 0; i < type.length && !valid; i++) {
          var assertedType = assertType(value, type[i]);
          expectedTypes.push(assertedType.expectedType || '');
          valid = assertedType.valid;
        }
      }
  
      if (!valid) {
        warn(
          getInvalidTypeMessage(name, value, expectedTypes),
          vm
        );
        return
      }
      var validator = prop.validator;
      if (validator) {
        if (!validator(value)) {
          warn(
            'Invalid prop: custom validator check failed for prop "' + name + '".',
            vm
          );
        }
      }
    }
  
    var simpleCheckRE = /^(String|Number|Boolean|Function|Symbol)$/;
  
    function assertType (value, type) {
      var valid;
      var expectedType = getType(type);
      if (simpleCheckRE.test(expectedType)) {
        var t = typeof value;
        valid = t === expectedType.toLowerCase();
        // for primitive wrapper objects
        if (!valid && t === 'object') {
          valid = value instanceof type;
        }
      } else if (expectedType === 'Object') {
        valid = isPlainObject(value);
      } else if (expectedType === 'Array') {
        valid = Array.isArray(value);
      } else {
        valid = value instanceof type;
      }
      return {
        valid: valid,
        expectedType: expectedType
      }
    }
  
    /**
     * Use function string name to check built-in types,
     * because a simple equality check will fail when running
     * across different vms / iframes.
     */
    function getType (fn) {
      var match = fn && fn.toString().match(/^\s*function (\w+)/);
      return match ? match[1] : ''
    }
  
    function isSameType (a, b) {
      return getType(a) === getType(b)
    }
  
    function getTypeIndex (type, expectedTypes) {
      if (!Array.isArray(expectedTypes)) {
        return isSameType(expectedTypes, type) ? 0 : -1
      }
      for (var i = 0, len = expectedTypes.length; i < len; i++) {
        if (isSameType(expectedTypes[i], type)) {
          return i
        }
      }
      return -1
    }
  
    function getInvalidTypeMessage (name, value, expectedTypes) {
      var message = "Invalid prop: type check failed for prop \"" + name + "\"." +
        " Expected " + (expectedTypes.map(capitalize).join(', '));
      var expectedType = expectedTypes[0];
      var receivedType = toRawType(value);
      var expectedValue = styleValue(value, expectedType);
      var receivedValue = styleValue(value, receivedType);
      // check if we need to specify expected value
      if (expectedTypes.length === 1 &&
          isExplicable(expectedType) &&
          !isBoolean(expectedType, receivedType)) {
        message += " with value " + expectedValue;
      }
      message += ", got " + receivedType + " ";
      // check if we need to specify received value
      if (isExplicable(receivedType)) {
        message += "with value " + receivedValue + ".";
      }
      return message
    }
  
    function styleValue (value, type) {
      if (type === 'String') {
        return ("\"" + value + "\"")
      } else if (type === 'Number') {
        return ("" + (Number(value)))
      } else {
        return ("" + value)
      }
    }
  
    function isExplicable (value) {
      var explicitTypes = ['string', 'number', 'boolean'];
      return explicitTypes.some(function (elem) { return value.toLowerCase() === elem; })
    }
  
    function isBoolean () {
      var args = [], len = arguments.length;
      while ( len-- ) args[ len ] = arguments[ len ];
  
      return args.some(function (elem) { return elem.toLowerCase() === 'boolean'; })
    }
  
    /*  */
  
    function handleError (err, vm, info) {
      // Deactivate deps tracking while processing error handler to avoid possible infinite rendering.
      // See: https://github.com/vuejs/vuex/issues/1505
      pushTarget();
      try {
        if (vm) {
          var cur = vm;
          while ((cur = cur.$parent)) {
            var hooks = cur.$options.errorCaptured;
            if (hooks) {
              for (var i = 0; i < hooks.length; i++) {
                try {
                  var capture = hooks[i].call(cur, err, vm, info) === false;
                  if (capture) { return }
                } catch (e) {
                  globalHandleError(e, cur, 'errorCaptured hook');
                }
              }
            }
          }
        }
        globalHandleError(err, vm, info);
      } finally {
        popTarget();
      }
    }
  
    function invokeWithErrorHandling (
      handler,
      context,
      args,
      vm,
      info
    ) {
      var res;
      try {
        res = args ? handler.apply(context, args) : handler.call(context);
        if (res && !res._isVue && isPromise(res) && !res._handled) {
          res.catch(function (e) { return handleError(e, vm, info + " (Promise/async)"); });
          // issue #9511
          // avoid catch triggering multiple times when nested calls
          res._handled = true;
        }
      } catch (e) {
        handleError(e, vm, info);
      }
      return res
    }
  
    function globalHandleError (err, vm, info) {
      if (config.errorHandler) {
        try {
          return config.errorHandler.call(null, err, vm, info)
        } catch (e) {
          // if the user intentionally throws the original error in the handler,
          // do not log it twice
          if (e !== err) {
            logError(e, null, 'config.errorHandler');
          }
        }
      }
      logError(err, vm, info);
    }
  
    function logError (err, vm, info) {
      {
        warn(("Error in " + info + ": \"" + (err.toString()) + "\""), vm);
      }
      /* istanbul ignore else */
      if ((inBrowser || inWeex) && typeof console !== 'undefined') {
        console.error(err);
      } else {
        throw err
      }
    }
  
    /*  */
  
    var isUsingMicroTask = false;
  
    var callbacks = [];
    var pending = false;
  
    function flushCallbacks() {
      pending = false;
      var copies = callbacks.slice(0);
      callbacks.length = 0;
      for (var i = 0; i < copies.length; i++) {
        copies[i]();
      }
    }
  
    // Here we have async deferring wrappers using microtasks.
    // In 2.5 we used (macro) tasks (in combination with microtasks).
    // However, it has subtle problems when state is changed right before repaint
    // (e.g. #6813, out-in transitions).
    // Also, using (macro) tasks in event handler would cause some weird behaviors
    // that cannot be circumvented (e.g. #7109, #7153, #7546, #7834, #8109).
    // So we now use microtasks everywhere, again.
    // A major drawback of this tradeoff is that there are some scenarios
    // where microtasks have too high a priority and fire in between supposedly
    // sequential events (e.g. #4521, #6690, which have workarounds)
    // or even between bubbling of the same event (#6566).
    var timerFunc;
  
    // The nextTick behavior leverages the microtask queue, which can be accessed
    // via either native Promise.then or MutationObserver.
    // MutationObserver has wider support, however it is seriously bugged in
    // UIWebView in iOS >= 9.3.3 when triggered in touch event handlers. It
    // completely stops working after triggering a few times... so, if native
    // Promise is available, we will use it:
    /* istanbul ignore next, $flow-disable-line */
    // 首选Promise
    if (typeof Promise !== 'undefined' && isNative(Promise)) {
      var p = Promise.resolve();
      timerFunc = function () {
        p.then(flushCallbacks);
        // In problematic UIWebViews, Promise.then doesn't completely break, but
        // it can get stuck in a weird state where callbacks are pushed into the
        // microtask queue but the queue isn't being flushed, until the browser
        // needs to do some other work, e.g. handle a timer. Therefore we can
        // "force" the microtask queue to be flushed by adding an empty timer.
        if (isIOS) { setTimeout(noop); }
      };
      isUsingMicroTask = true;
    } else if (!isIE && typeof MutationObserver !== 'undefined' && (
      isNative(MutationObserver) ||
      // PhantomJS and iOS 7.x
      MutationObserver.toString() === '[object MutationObserverConstructor]'
    )) {
      // Use MutationObserver where native Promise is not available,
      // e.g. PhantomJS, iOS7, Android 4.4
      // (#6466 MutationObserver is unreliable in IE11)
      var counter = 1;
      var observer = new MutationObserver(flushCallbacks);
      var textNode = document.createTextNode(String(counter));
      observer.observe(textNode, {
        characterData: true
      });
      timerFunc = function () {
        counter = (counter + 1) % 2;
        textNode.data = String(counter);
      };
      isUsingMicroTask = true;
    } else if (typeof setImmediate !== 'undefined' && isNative(setImmediate)) {
      // Fallback to setImmediate.
      // Technically it leverages the (macro) task queue,
      // but it is still a better choice than setTimeout.
      timerFunc = function () {
        setImmediate(flushCallbacks);
      };
    } else {
      // Fallback to setTimeout.
      timerFunc = function () {
        setTimeout(flushCallbacks, 0);
      };
    }
  
    // 此方式就是$nextTick
    // this.$nextTick(() => {})
    function nextTick(cb, ctx) {
      var _resolve;
      // 用户传递的回调函数会被放入callbacks里
      // 前面的刷新函数（flushSchedulerQueue）就是执行callback中的所有回调
      callbacks.push(function () {
        if (cb) {
          try {
            cb.call(ctx);
          } catch (e) {
            handleError(e, ctx, 'nextTick');
          }
        } else if (_resolve) {
          _resolve(ctx);
        }
      });
      if (!pending) {
        pending = true;
        // 定时器函数启动
        timerFunc();
      }
      // $flow-disable-line
      if (!cb && typeof Promise !== 'undefined') {
        return new Promise(function (resolve) {
          _resolve = resolve;
        })
      }
    }
  
    var mark;
    var measure;
  
    {
      var perf = inBrowser && window.performance;
      /* istanbul ignore if */
      if (
        perf &&
        perf.mark &&
        perf.measure &&
        perf.clearMarks &&
        perf.clearMeasures
      ) {
        mark = function (tag) { return perf.mark(tag); };
        measure = function (name, startTag, endTag) {
          perf.measure(name, startTag, endTag);
          perf.clearMarks(startTag);
          perf.clearMarks(endTag);
          // perf.clearMeasures(name)
        };
      }
    }
  
    /* not type checking this file because flow doesn't play well with Proxy */
  
    var initProxy;
  
    {
      var allowedGlobals = makeMap(
        'Infinity,undefined,NaN,isFinite,isNaN,' +
        'parseFloat,parseInt,decodeURI,decodeURIComponent,encodeURI,encodeURIComponent,' +
        'Math,Number,Date,Array,Object,Boolean,String,RegExp,Map,Set,JSON,Intl,' +
        'require' // for Webpack/Browserify
      );
  
      var warnNonPresent = function (target, key) {
        warn(
          "Property or method \"" + key + "\" is not defined on the instance but " +
          'referenced during render. Make sure that this property is reactive, ' +
          'either in the data option, or for class-based components, by ' +
          'initializing the property. ' +
          'See: https://vuejs.org/v2/guide/reactivity.html#Declaring-Reactive-Properties.',
          target
        );
      };
  
      var warnReservedPrefix = function (target, key) {
        warn(
          "Property \"" + key + "\" must be accessed with \"$data." + key + "\" because " +
          'properties starting with "$" or "_" are not proxied in the Vue instance to ' +
          'prevent conflicts with Vue internals. ' +
          'See: https://vuejs.org/v2/api/#data',
          target
        );
      };
  
      var hasProxy =
        typeof Proxy !== 'undefined' && isNative(Proxy);
  
      if (hasProxy) {
        var isBuiltInModifier = makeMap('stop,prevent,self,ctrl,shift,alt,meta,exact');
        config.keyCodes = new Proxy(config.keyCodes, {
          set: function set (target, key, value) {
            if (isBuiltInModifier(key)) {
              warn(("Avoid overwriting built-in modifier in config.keyCodes: ." + key));
              return false
            } else {
              target[key] = value;
              return true
            }
          }
        });
      }
  
      var hasHandler = {
        has: function has (target, key) {
          var has = key in target;
          var isAllowed = allowedGlobals(key) ||
            (typeof key === 'string' && key.charAt(0) === '_' && !(key in target.$data));
          if (!has && !isAllowed) {
            if (key in target.$data) { warnReservedPrefix(target, key); }
            else { warnNonPresent(target, key); }
          }
          return has || !isAllowed
        }
      };
  
      var getHandler = {
        get: function get (target, key) {
          if (typeof key === 'string' && !(key in target)) {
            if (key in target.$data) { warnReservedPrefix(target, key); }
            else { warnNonPresent(target, key); }
          }
          return target[key]
        }
      };
  
      initProxy = function initProxy (vm) {
        if (hasProxy) {
          // determine which proxy handler to use
          var options = vm.$options;
          var handlers = options.render && options.render._withStripped
            ? getHandler
            : hasHandler;
          vm._renderProxy = new Proxy(vm, handlers);
        } else {
          vm._renderProxy = vm;
        }
      };
    }
  
    /*  */
  
    var seenObjects = new _Set();
  
    /**
     * Recursively traverse an object to evoke all converted
     * getters, so that every nested property inside the object
     * is collected as a "deep" dependency.
     */
    function traverse (val) {
      _traverse(val, seenObjects);
      seenObjects.clear();
    }
  
    function _traverse (val, seen) {
      var i, keys;
      var isA = Array.isArray(val);
      if ((!isA && !isObject(val)) || Object.isFrozen(val) || val instanceof VNode) {
        return
      }
      if (val.__ob__) {
        var depId = val.__ob__.dep.id;
        if (seen.has(depId)) {
          return
        }
        seen.add(depId);
      }
      if (isA) {
        i = val.length;
        while (i--) { _traverse(val[i], seen); }
      } else {
        keys = Object.keys(val);
        i = keys.length;
        while (i--) { _traverse(val[keys[i]], seen); }
      }
    }
  
    /*  */
  
    var normalizeEvent = cached(function (name) {
      var passive = name.charAt(0) === '&';
      name = passive ? name.slice(1) : name;
      var once = name.charAt(0) === '~'; // Prefixed last, checked first
      name = once ? name.slice(1) : name;
      var capture = name.charAt(0) === '!';
      name = capture ? name.slice(1) : name;
      return {
        name: name,
        once: once,
        capture: capture,
        passive: passive
      }
    });
  
    function createFnInvoker (fns, vm) {
      function invoker () {
        var arguments$1 = arguments;
  
        var fns = invoker.fns;
        if (Array.isArray(fns)) {
          var cloned = fns.slice();
          for (var i = 0; i < cloned.length; i++) {
            invokeWithErrorHandling(cloned[i], null, arguments$1, vm, "v-on handler");
          }
        } else {
          // return handler return value for single handlers
          return invokeWithErrorHandling(fns, null, arguments, vm, "v-on handler")
        }
      }
      invoker.fns = fns;
      return invoker
    }
  
    function updateListeners (
      on,
      oldOn,
      add,
      remove,
      createOnceHandler,
      vm
    ) {
      var name, def, cur, old, event;
      for (name in on) {
        def = cur = on[name];
        old = oldOn[name];
        event = normalizeEvent(name);
        if (isUndef(cur)) {
           warn(
            "Invalid handler for event \"" + (event.name) + "\": got " + String(cur),
            vm
          );
        } else if (isUndef(old)) {
          if (isUndef(cur.fns)) {
            cur = on[name] = createFnInvoker(cur, vm);
          }
          if (isTrue(event.once)) {
            cur = on[name] = createOnceHandler(event.name, cur, event.capture);
          }
          add(event.name, cur, event.capture, event.passive, event.params);
        } else if (cur !== old) {
          old.fns = cur;
          on[name] = old;
        }
      }
      for (name in oldOn) {
        if (isUndef(on[name])) {
          event = normalizeEvent(name);
          remove(event.name, oldOn[name], event.capture);
        }
      }
    }
  
    /*  */
  
    function mergeVNodeHook (def, hookKey, hook) {
      if (def instanceof VNode) {
        def = def.data.hook || (def.data.hook = {});
      }
      var invoker;
      var oldHook = def[hookKey];
  
      function wrappedHook () {
        hook.apply(this, arguments);
        // important: remove merged hook to ensure it's called only once
        // and prevent memory leak
        remove(invoker.fns, wrappedHook);
      }
  
      if (isUndef(oldHook)) {
        // no existing hook
        invoker = createFnInvoker([wrappedHook]);
      } else {
        /* istanbul ignore if */
        if (isDef(oldHook.fns) && isTrue(oldHook.merged)) {
          // already a merged invoker
          invoker = oldHook;
          invoker.fns.push(wrappedHook);
        } else {
          // existing plain hook
          invoker = createFnInvoker([oldHook, wrappedHook]);
        }
      }
  
      invoker.merged = true;
      def[hookKey] = invoker;
    }
  
    /*  */
  
    function extractPropsFromVNodeData (
      data,
      Ctor,
      tag
    ) {
      // we are only extracting raw values here.
      // validation and default values are handled in the child
      // component itself.
      var propOptions = Ctor.options.props;
      if (isUndef(propOptions)) {
        return
      }
      var res = {};
      var attrs = data.attrs;
      var props = data.props;
      if (isDef(attrs) || isDef(props)) {
        for (var key in propOptions) {
          var altKey = hyphenate(key);
          {
            var keyInLowerCase = key.toLowerCase();
            if (
              key !== keyInLowerCase &&
              attrs && hasOwn(attrs, keyInLowerCase)
            ) {
              tip(
                "Prop \"" + keyInLowerCase + "\" is passed to component " +
                (formatComponentName(tag || Ctor)) + ", but the declared prop name is" +
                " \"" + key + "\". " +
                "Note that HTML attributes are case-insensitive and camelCased " +
                "props need to use their kebab-case equivalents when using in-DOM " +
                "templates. You should probably use \"" + altKey + "\" instead of \"" + key + "\"."
              );
            }
          }
          checkProp(res, props, key, altKey, true) ||
          checkProp(res, attrs, key, altKey, false);
        }
      }
      return res
    }
  
    function checkProp (
      res,
      hash,
      key,
      altKey,
      preserve
    ) {
      if (isDef(hash)) {
        if (hasOwn(hash, key)) {
          res[key] = hash[key];
          if (!preserve) {
            delete hash[key];
          }
          return true
        } else if (hasOwn(hash, altKey)) {
          res[key] = hash[altKey];
          if (!preserve) {
            delete hash[altKey];
          }
          return true
        }
      }
      return false
    }
  
    /*  */
  
    // The template compiler attempts to minimize the need for normalization by
    // statically analyzing the template at compile time.
    //
    // For plain HTML markup, normalization can be completely skipped because the
    // generated render function is guaranteed to return Array<VNode>. There are
    // two cases where extra normalization is needed:
  
    // 1. When the children contains components - because a functional component
    // may return an Array instead of a single root. In this case, just a simple
    // normalization is needed - if any child is an Array, we flatten the whole
    // thing with Array.prototype.concat. It is guaranteed to be only 1-level deep
    // because functional components already normalize their own children.
    function simpleNormalizeChildren (children) {
      for (var i = 0; i < children.length; i++) {
        if (Array.isArray(children[i])) {
          return Array.prototype.concat.apply([], children)
        }
      }
      return children
    }
  
    // 2. When the children contains constructs that always generated nested Arrays,
    // e.g. <template>, <slot>, v-for, or when the children is provided by user
    // with hand-written render functions / JSX. In such cases a full normalization
    // is needed to cater to all possible types of children values.
    function normalizeChildren (children) {
      return isPrimitive(children)
        ? [createTextVNode(children)]
        : Array.isArray(children)
          ? normalizeArrayChildren(children)
          : undefined
    }
  
    function isTextNode (node) {
      return isDef(node) && isDef(node.text) && isFalse(node.isComment)
    }
  
    function normalizeArrayChildren (children, nestedIndex) {
      var res = [];
      var i, c, lastIndex, last;
      for (i = 0; i < children.length; i++) {
        c = children[i];
        if (isUndef(c) || typeof c === 'boolean') { continue }
        lastIndex = res.length - 1;
        last = res[lastIndex];
        //  nested
        if (Array.isArray(c)) {
          if (c.length > 0) {
            c = normalizeArrayChildren(c, ((nestedIndex || '') + "_" + i));
            // merge adjacent text nodes
            if (isTextNode(c[0]) && isTextNode(last)) {
              res[lastIndex] = createTextVNode(last.text + (c[0]).text);
              c.shift();
            }
            res.push.apply(res, c);
          }
        } else if (isPrimitive(c)) {
          if (isTextNode(last)) {
            // merge adjacent text nodes
            // this is necessary for SSR hydration because text nodes are
            // essentially merged when rendered to HTML strings
            res[lastIndex] = createTextVNode(last.text + c);
          } else if (c !== '') {
            // convert primitive to vnode
            res.push(createTextVNode(c));
          }
        } else {
          if (isTextNode(c) && isTextNode(last)) {
            // merge adjacent text nodes
            res[lastIndex] = createTextVNode(last.text + c.text);
          } else {
            // default key for nested array children (likely generated by v-for)
            if (isTrue(children._isVList) &&
              isDef(c.tag) &&
              isUndef(c.key) &&
              isDef(nestedIndex)) {
              c.key = "__vlist" + nestedIndex + "_" + i + "__";
            }
            res.push(c);
          }
        }
      }
      return res
    }
  
    /*  */
  
    function initProvide (vm) {
      var provide = vm.$options.provide;
      if (provide) {
        vm._provided = typeof provide === 'function'
          ? provide.call(vm)
          : provide;
      }
    }
  
    function initInjections (vm) {
      var result = resolveInject(vm.$options.inject, vm);
      if (result) {
        toggleObserving(false);
        Object.keys(result).forEach(function (key) {
          /* istanbul ignore else */
          {
            defineReactive(vm, key, result[key], function () {
              warn(
                "Avoid mutating an injected value directly since the changes will be " +
                "overwritten whenever the provided component re-renders. " +
                "injection being mutated: \"" + key + "\"",
                vm
              );
            });
          }
        });
        toggleObserving(true);
      }
    }
  
    function resolveInject (inject, vm) {
      if (inject) {
        // inject is :any because flow is not smart enough to figure out cached
        var result = Object.create(null);
        var keys = hasSymbol
          ? Reflect.ownKeys(inject)
          : Object.keys(inject);
  
        for (var i = 0; i < keys.length; i++) {
          var key = keys[i];
          // #6574 in case the inject object is observed...
          if (key === '__ob__') { continue }
          var provideKey = inject[key].from;
          var source = vm;
          while (source) {
            if (source._provided && hasOwn(source._provided, provideKey)) {
              result[key] = source._provided[provideKey];
              break
            }
            source = source.$parent;
          }
          if (!source) {
            if ('default' in inject[key]) {
              var provideDefault = inject[key].default;
              result[key] = typeof provideDefault === 'function'
                ? provideDefault.call(vm)
                : provideDefault;
            } else {
              warn(("Injection \"" + key + "\" not found"), vm);
            }
          }
        }
        return result
      }
    }
  
    /*  */
  
  
  
    /**
     * Runtime helper for resolving raw children VNodes into a slot object.
     */
    function resolveSlots (
      children,
      context
    ) {
      if (!children || !children.length) {
        return {}
      }
      var slots = {};
      for (var i = 0, l = children.length; i < l; i++) {
        var child = children[i];
        var data = child.data;
        // remove slot attribute if the node is resolved as a Vue slot node
        if (data && data.attrs && data.attrs.slot) {
          delete data.attrs.slot;
        }
        // named slots should only be respected if the vnode was rendered in the
        // same context.
        if ((child.context === context || child.fnContext === context) &&
          data && data.slot != null
        ) {
          var name = data.slot;
          var slot = (slots[name] || (slots[name] = []));
          if (child.tag === 'template') {
            slot.push.apply(slot, child.children || []);
          } else {
            slot.push(child);
          }
        } else {
          (slots.default || (slots.default = [])).push(child);
        }
      }
      // ignore slots that contains only whitespace
      for (var name$1 in slots) {
        if (slots[name$1].every(isWhitespace)) {
          delete slots[name$1];
        }
      }
      return slots
    }
  
    function isWhitespace (node) {
      return (node.isComment && !node.asyncFactory) || node.text === ' '
    }
  
    /*  */
  
    function normalizeScopedSlots (
      slots,
      normalSlots,
      prevSlots
    ) {
      var res;
      var hasNormalSlots = Object.keys(normalSlots).length > 0;
      var isStable = slots ? !!slots.$stable : !hasNormalSlots;
      var key = slots && slots.$key;
      if (!slots) {
        res = {};
      } else if (slots._normalized) {
        // fast path 1: child component re-render only, parent did not change
        return slots._normalized
      } else if (
        isStable &&
        prevSlots &&
        prevSlots !== emptyObject &&
        key === prevSlots.$key &&
        !hasNormalSlots &&
        !prevSlots.$hasNormal
      ) {
        // fast path 2: stable scoped slots w/ no normal slots to proxy,
        // only need to normalize once
        return prevSlots
      } else {
        res = {};
        for (var key$1 in slots) {
          if (slots[key$1] && key$1[0] !== '$') {
            res[key$1] = normalizeScopedSlot(normalSlots, key$1, slots[key$1]);
          }
        }
      }
      // expose normal slots on scopedSlots
      for (var key$2 in normalSlots) {
        if (!(key$2 in res)) {
          res[key$2] = proxyNormalSlot(normalSlots, key$2);
        }
      }
      // avoriaz seems to mock a non-extensible $scopedSlots object
      // and when that is passed down this would cause an error
      if (slots && Object.isExtensible(slots)) {
        (slots)._normalized = res;
      }
      def(res, '$stable', isStable);
      def(res, '$key', key);
      def(res, '$hasNormal', hasNormalSlots);
      return res
    }
  
    function normalizeScopedSlot(normalSlots, key, fn) {
      var normalized = function () {
        var res = arguments.length ? fn.apply(null, arguments) : fn({});
        res = res && typeof res === 'object' && !Array.isArray(res)
          ? [res] // single vnode
          : normalizeChildren(res);
        return res && (
          res.length === 0 ||
          (res.length === 1 && res[0].isComment) // #9658
        ) ? undefined
          : res
      };
      // this is a slot using the new v-slot syntax without scope. although it is
      // compiled as a scoped slot, render fn users would expect it to be present
      // on this.$slots because the usage is semantically a normal slot.
      if (fn.proxy) {
        Object.defineProperty(normalSlots, key, {
          get: normalized,
          enumerable: true,
          configurable: true
        });
      }
      return normalized
    }
  
    function proxyNormalSlot(slots, key) {
      return function () { return slots[key]; }
    }
  
    /*  */
  
    /**
     * Runtime helper for rendering v-for lists.
     */
    function renderList (
      val,
      render
    ) {
      var ret, i, l, keys, key;
      if (Array.isArray(val) || typeof val === 'string') {
        ret = new Array(val.length);
        for (i = 0, l = val.length; i < l; i++) {
          ret[i] = render(val[i], i);
        }
      } else if (typeof val === 'number') {
        ret = new Array(val);
        for (i = 0; i < val; i++) {
          ret[i] = render(i + 1, i);
        }
      } else if (isObject(val)) {
        if (hasSymbol && val[Symbol.iterator]) {
          ret = [];
          var iterator = val[Symbol.iterator]();
          var result = iterator.next();
          while (!result.done) {
            ret.push(render(result.value, ret.length));
            result = iterator.next();
          }
        } else {
          keys = Object.keys(val);
          ret = new Array(keys.length);
          for (i = 0, l = keys.length; i < l; i++) {
            key = keys[i];
            ret[i] = render(val[key], key, i);
          }
        }
      }
      if (!isDef(ret)) {
        ret = [];
      }
      (ret)._isVList = true;
      return ret
    }
  
    /*  */
  
    /**
     * Runtime helper for rendering <slot>
     */
    function renderSlot (
      name,
      fallback,
      props,
      bindObject
    ) {
      var scopedSlotFn = this.$scopedSlots[name];
      var nodes;
      if (scopedSlotFn) { // scoped slot
        props = props || {};
        if (bindObject) {
          if ( !isObject(bindObject)) {
            warn(
              'slot v-bind without argument expects an Object',
              this
            );
          }
          props = extend(extend({}, bindObject), props);
        }
        nodes = scopedSlotFn(props) || fallback;
      } else {
        nodes = this.$slots[name] || fallback;
      }
  
      var target = props && props.slot;
      if (target) {
        return this.$createElement('template', { slot: target }, nodes)
      } else {
        return nodes
      }
    }
  
    /*  */
  
    /**
     * Runtime helper for resolving filters
     */
    function resolveFilter (id) {
      return resolveAsset(this.$options, 'filters', id, true) || identity
    }
  
    /*  */
  
    function isKeyNotMatch (expect, actual) {
      if (Array.isArray(expect)) {
        return expect.indexOf(actual) === -1
      } else {
        return expect !== actual
      }
    }
  
    /**
     * Runtime helper for checking keyCodes from config.
     * exposed as Vue.prototype._k
     * passing in eventKeyName as last argument separately for backwards compat
     */
    function checkKeyCodes (
      eventKeyCode,
      key,
      builtInKeyCode,
      eventKeyName,
      builtInKeyName
    ) {
      var mappedKeyCode = config.keyCodes[key] || builtInKeyCode;
      if (builtInKeyName && eventKeyName && !config.keyCodes[key]) {
        return isKeyNotMatch(builtInKeyName, eventKeyName)
      } else if (mappedKeyCode) {
        return isKeyNotMatch(mappedKeyCode, eventKeyCode)
      } else if (eventKeyName) {
        return hyphenate(eventKeyName) !== key
      }
    }
  
    /*  */
  
    /**
     * Runtime helper for merging v-bind="object" into a VNode's data.
     */
    function bindObjectProps (
      data,
      tag,
      value,
      asProp,
      isSync
    ) {
      if (value) {
        if (!isObject(value)) {
           warn(
            'v-bind without argument expects an Object or Array value',
            this
          );
        } else {
          if (Array.isArray(value)) {
            value = toObject(value);
          }
          var hash;
          var loop = function ( key ) {
            if (
              key === 'class' ||
              key === 'style' ||
              isReservedAttribute(key)
            ) {
              hash = data;
            } else {
              var type = data.attrs && data.attrs.type;
              hash = asProp || config.mustUseProp(tag, type, key)
                ? data.domProps || (data.domProps = {})
                : data.attrs || (data.attrs = {});
            }
            var camelizedKey = camelize(key);
            var hyphenatedKey = hyphenate(key);
            if (!(camelizedKey in hash) && !(hyphenatedKey in hash)) {
              hash[key] = value[key];
  
              if (isSync) {
                var on = data.on || (data.on = {});
                on[("update:" + key)] = function ($event) {
                  value[key] = $event;
                };
              }
            }
          };
  
          for (var key in value) loop( key );
        }
      }
      return data
    }
  
    /*  */
  
    /**
     * Runtime helper for rendering static trees.
     */
    function renderStatic (
      index,
      isInFor
    ) {
      var cached = this._staticTrees || (this._staticTrees = []);
      var tree = cached[index];
      // if has already-rendered static tree and not inside v-for,
      // we can reuse the same tree.
      if (tree && !isInFor) {
        return tree
      }
      // otherwise, render a fresh tree.
      tree = cached[index] = this.$options.staticRenderFns[index].call(
        this._renderProxy,
        null,
        this // for render fns generated for functional component templates
      );
      markStatic(tree, ("__static__" + index), false);
      return tree
    }
  
    /**
     * Runtime helper for v-once.
     * Effectively it means marking the node as static with a unique key.
     */
    function markOnce (
      tree,
      index,
      key
    ) {
      markStatic(tree, ("__once__" + index + (key ? ("_" + key) : "")), true);
      return tree
    }
  
    function markStatic (
      tree,
      key,
      isOnce
    ) {
      if (Array.isArray(tree)) {
        for (var i = 0; i < tree.length; i++) {
          if (tree[i] && typeof tree[i] !== 'string') {
            markStaticNode(tree[i], (key + "_" + i), isOnce);
          }
        }
      } else {
        markStaticNode(tree, key, isOnce);
      }
    }
  
    function markStaticNode (node, key, isOnce) {
      node.isStatic = true;
      node.key = key;
      node.isOnce = isOnce;
    }
  
    /*  */
  
    function bindObjectListeners (data, value) {
      if (value) {
        if (!isPlainObject(value)) {
           warn(
            'v-on without argument expects an Object value',
            this
          );
        } else {
          var on = data.on = data.on ? extend({}, data.on) : {};
          for (var key in value) {
            var existing = on[key];
            var ours = value[key];
            on[key] = existing ? [].concat(existing, ours) : ours;
          }
        }
      }
      return data
    }
  
    /*  */
  
    function resolveScopedSlots (
      fns, // see flow/vnode
      res,
      // the following are added in 2.6
      hasDynamicKeys,
      contentHashKey
    ) {
      res = res || { $stable: !hasDynamicKeys };
      for (var i = 0; i < fns.length; i++) {
        var slot = fns[i];
        if (Array.isArray(slot)) {
          resolveScopedSlots(slot, res, hasDynamicKeys);
        } else if (slot) {
          // marker for reverse proxying v-slot without scope on this.$slots
          if (slot.proxy) {
            slot.fn.proxy = true;
          }
          res[slot.key] = slot.fn;
        }
      }
      if (contentHashKey) {
        (res).$key = contentHashKey;
      }
      return res
    }
  
    /*  */
  
    function bindDynamicKeys (baseObj, values) {
      for (var i = 0; i < values.length; i += 2) {
        var key = values[i];
        if (typeof key === 'string' && key) {
          baseObj[values[i]] = values[i + 1];
        } else if ( key !== '' && key !== null) {
          // null is a special value for explicitly removing a binding
          warn(
            ("Invalid value for dynamic directive argument (expected string or null): " + key),
            this
          );
        }
      }
      return baseObj
    }
  
    // helper to dynamically append modifier runtime markers to event names.
    // ensure only append when value is already string, otherwise it will be cast
    // to string and cause the type check to miss.
    function prependModifier (value, symbol) {
      return typeof value === 'string' ? symbol + value : value
    }
  
    /*  */
  
    function installRenderHelpers (target) {
      target._o = markOnce;
      target._n = toNumber;
      target._s = toString;
      target._l = renderList;
      target._t = renderSlot;
      target._q = looseEqual;
      target._i = looseIndexOf;
      target._m = renderStatic;
      target._f = resolveFilter;
      target._k = checkKeyCodes;
      target._b = bindObjectProps;
      target._v = createTextVNode;
      target._e = createEmptyVNode;
      target._u = resolveScopedSlots;
      target._g = bindObjectListeners;
      target._d = bindDynamicKeys;
      target._p = prependModifier;
    }
  
    /*  */
  
    function FunctionalRenderContext (
      data,
      props,
      children,
      parent,
      Ctor
    ) {
      var this$1 = this;
  
      var options = Ctor.options;
      // ensure the createElement function in functional components
      // gets a unique context - this is necessary for correct named slot check
      var contextVm;
      if (hasOwn(parent, '_uid')) {
        contextVm = Object.create(parent);
        // $flow-disable-line
        contextVm._original = parent;
      } else {
        // the context vm passed in is a functional context as well.
        // in this case we want to make sure we are able to get a hold to the
        // real context instance.
        contextVm = parent;
        // $flow-disable-line
        parent = parent._original;
      }
      var isCompiled = isTrue(options._compiled);
      var needNormalization = !isCompiled;
  
      this.data = data;
      this.props = props;
      this.children = children;
      this.parent = parent;
      this.listeners = data.on || emptyObject;
      this.injections = resolveInject(options.inject, parent);
      this.slots = function () {
        if (!this$1.$slots) {
          normalizeScopedSlots(
            data.scopedSlots,
            this$1.$slots = resolveSlots(children, parent)
          );
        }
        return this$1.$slots
      };
  
      Object.defineProperty(this, 'scopedSlots', ({
        enumerable: true,
        get: function get () {
          return normalizeScopedSlots(data.scopedSlots, this.slots())
        }
      }));
  
      // support for compiled functional template
      if (isCompiled) {
        // exposing $options for renderStatic()
        this.$options = options;
        // pre-resolve slots for renderSlot()
        this.$slots = this.slots();
        this.$scopedSlots = normalizeScopedSlots(data.scopedSlots, this.$slots);
      }
  
      if (options._scopeId) {
        this._c = function (a, b, c, d) {
          var vnode = createElement(contextVm, a, b, c, d, needNormalization);
          if (vnode && !Array.isArray(vnode)) {
            vnode.fnScopeId = options._scopeId;
            vnode.fnContext = parent;
          }
          return vnode
        };
      } else {
        this._c = function (a, b, c, d) { return createElement(contextVm, a, b, c, d, needNormalization); };
      }
    }
  
    installRenderHelpers(FunctionalRenderContext.prototype);
  
    function createFunctionalComponent (
      Ctor,
      propsData,
      data,
      contextVm,
      children
    ) {
      var options = Ctor.options;
      var props = {};
      var propOptions = options.props;
      if (isDef(propOptions)) {
        for (var key in propOptions) {
          props[key] = validateProp(key, propOptions, propsData || emptyObject);
        }
      } else {
        if (isDef(data.attrs)) { mergeProps(props, data.attrs); }
        if (isDef(data.props)) { mergeProps(props, data.props); }
      }
  
      var renderContext = new FunctionalRenderContext(
        data,
        props,
        children,
        contextVm,
        Ctor
      );
  
      var vnode = options.render.call(null, renderContext._c, renderContext);
  
      if (vnode instanceof VNode) {
        return cloneAndMarkFunctionalResult(vnode, data, renderContext.parent, options, renderContext)
      } else if (Array.isArray(vnode)) {
        var vnodes = normalizeChildren(vnode) || [];
        var res = new Array(vnodes.length);
        for (var i = 0; i < vnodes.length; i++) {
          res[i] = cloneAndMarkFunctionalResult(vnodes[i], data, renderContext.parent, options, renderContext);
        }
        return res
      }
    }
  
    function cloneAndMarkFunctionalResult (vnode, data, contextVm, options, renderContext) {
      // #7817 clone node before setting fnContext, otherwise if the node is reused
      // (e.g. it was from a cached normal slot) the fnContext causes named slots
      // that should not be matched to match.
      var clone = cloneVNode(vnode);
      clone.fnContext = contextVm;
      clone.fnOptions = options;
      {
        (clone.devtoolsMeta = clone.devtoolsMeta || {}).renderContext = renderContext;
      }
      if (data.slot) {
        (clone.data || (clone.data = {})).slot = data.slot;
      }
      return clone
    }
  
    function mergeProps (to, from) {
      for (var key in from) {
        to[camelize(key)] = from[key];
      }
    }
  
    /*  */
  
    // inline hooks to be invoked on component VNodes during patch
    var componentVNodeHooks = {
      init: function init (vnode, hydrating) {
        if (
          vnode.componentInstance &&
          !vnode.componentInstance._isDestroyed &&
          vnode.data.keepAlive
        ) {
          // kept-alive components, treat as a patch
          var mountedNode = vnode; // work around flow
          componentVNodeHooks.prepatch(mountedNode, mountedNode);
        } else {
          var child = vnode.componentInstance = createComponentInstanceForVnode(
            vnode,
            activeInstance
          );
          child.$mount(hydrating ? vnode.elm : undefined, hydrating);
        }
      },
  
      prepatch: function prepatch (oldVnode, vnode) {
        var options = vnode.componentOptions;
        var child = vnode.componentInstance = oldVnode.componentInstance;
        updateChildComponent(
          child,
          options.propsData, // updated props
          options.listeners, // updated listeners
          vnode, // new parent vnode
          options.children // new children
        );
      },
  
      insert: function insert (vnode) {
        var context = vnode.context;
        var componentInstance = vnode.componentInstance;
        if (!componentInstance._isMounted) {
          componentInstance._isMounted = true;
          callHook(componentInstance, 'mounted');
        }
        if (vnode.data.keepAlive) {
          if (context._isMounted) {
            // vue-router#1212
            // During updates, a kept-alive component's child components may
            // change, so directly walking the tree here may call activated hooks
            // on incorrect children. Instead we push them into a queue which will
            // be processed after the whole patch process ended.
            queueActivatedComponent(componentInstance);
          } else {
            activateChildComponent(componentInstance, true /* direct */);
          }
        }
      },
  
      destroy: function destroy (vnode) {
        var componentInstance = vnode.componentInstance;
        if (!componentInstance._isDestroyed) {
          if (!vnode.data.keepAlive) {
            componentInstance.$destroy();
          } else {
            deactivateChildComponent(componentInstance, true /* direct */);
          }
        }
      }
    };
  
    var hooksToMerge = Object.keys(componentVNodeHooks);
  
    function createComponent (
      Ctor,
      data,
      context,
      children,
      tag
    ) {
      if (isUndef(Ctor)) {
        return
      }
  
      var baseCtor = context.$options._base;
  
      // plain options object: turn it into a constructor
      if (isObject(Ctor)) {
        Ctor = baseCtor.extend(Ctor);
      }
  
      // if at this stage it's not a constructor or an async component factory,
      // reject.
      if (typeof Ctor !== 'function') {
        {
          warn(("Invalid Component definition: " + (String(Ctor))), context);
        }
        return
      }
  
      // async component
      var asyncFactory;
      if (isUndef(Ctor.cid)) {
        asyncFactory = Ctor;
        Ctor = resolveAsyncComponent(asyncFactory, baseCtor);
        if (Ctor === undefined) {
          // return a placeholder node for async component, which is rendered
          // as a comment node but preserves all the raw information for the node.
          // the information will be used for async server-rendering and hydration.
          return createAsyncPlaceholder(
            asyncFactory,
            data,
            context,
            children,
            tag
          )
        }
      }
  
      data = data || {};
  
      // resolve constructor options in case global mixins are applied after
      // component constructor creation
      resolveConstructorOptions(Ctor);
  
      // transform component v-model data into props & events
      if (isDef(data.model)) {
        transformModel(Ctor.options, data);
      }
  
      // extract props
      var propsData = extractPropsFromVNodeData(data, Ctor, tag);
  
      // functional component
      if (isTrue(Ctor.options.functional)) {
        return createFunctionalComponent(Ctor, propsData, data, context, children)
      }
  
      // extract listeners, since these needs to be treated as
      // child component listeners instead of DOM listeners
      var listeners = data.on;
      // replace with listeners with .native modifier
      // so it gets processed during parent component patch.
      data.on = data.nativeOn;
  
      if (isTrue(Ctor.options.abstract)) {
        // abstract components do not keep anything
        // other than props & listeners & slot
  
        // work around flow
        var slot = data.slot;
        data = {};
        if (slot) {
          data.slot = slot;
        }
      }
  
      // install component management hooks onto the placeholder node
      installComponentHooks(data);
  
      // return a placeholder vnode
      var name = Ctor.options.name || tag;
      var vnode = new VNode(
        ("vue-component-" + (Ctor.cid) + (name ? ("-" + name) : '')),
        data, undefined, undefined, undefined, context,
        { Ctor: Ctor, propsData: propsData, listeners: listeners, tag: tag, children: children },
        asyncFactory
      );
  
      return vnode
    }
  
    function createComponentInstanceForVnode (
      vnode, // we know it's MountedComponentVNode but flow doesn't
      parent // activeInstance in lifecycle state
    ) {
      var options = {
        _isComponent: true,
        _parentVnode: vnode,
        parent: parent
      };
      // check inline-template render functions
      var inlineTemplate = vnode.data.inlineTemplate;
      if (isDef(inlineTemplate)) {
        options.render = inlineTemplate.render;
        options.staticRenderFns = inlineTemplate.staticRenderFns;
      }
      return new vnode.componentOptions.Ctor(options)
    }
  
    function installComponentHooks (data) {
      var hooks = data.hook || (data.hook = {});
      for (var i = 0; i < hooksToMerge.length; i++) {
        var key = hooksToMerge[i];
        var existing = hooks[key];
        var toMerge = componentVNodeHooks[key];
        if (existing !== toMerge && !(existing && existing._merged)) {
          hooks[key] = existing ? mergeHook$1(toMerge, existing) : toMerge;
        }
      }
    }
  
    function mergeHook$1 (f1, f2) {
      var merged = function (a, b) {
        // flow complains about extra args which is why we use any
        f1(a, b);
        f2(a, b);
      };
      merged._merged = true;
      return merged
    }
  
    // transform component v-model info (value and callback) into
    // prop and event handler respectively.
    function transformModel (options, data) {
      var prop = (options.model && options.model.prop) || 'value';
      var event = (options.model && options.model.event) || 'input'
      ;(data.attrs || (data.attrs = {}))[prop] = data.model.value;
      var on = data.on || (data.on = {});
      var existing = on[event];
      var callback = data.model.callback;
      if (isDef(existing)) {
        if (
          Array.isArray(existing)
            ? existing.indexOf(callback) === -1
            : existing !== callback
        ) {
          on[event] = [callback].concat(existing);
        }
      } else {
        on[event] = callback;
      }
    }
  
    /*  */
  
    var SIMPLE_NORMALIZE = 1;
    var ALWAYS_NORMALIZE = 2;
  
    // wrapper function for providing a more flexible interface
    // without getting yelled at by flow
    function createElement(
      context,
      tag,
      data,
      children,
      normalizationType,
      alwaysNormalize
    ) {
      if (Array.isArray(data) || isPrimitive(data)) {
        normalizationType = children;
        children = data;
        data = undefined;
      }
      if (isTrue(alwaysNormalize)) {
        normalizationType = ALWAYS_NORMALIZE;
      }
      return _createElement(context, tag, data, children, normalizationType)
    }
  
    //传入的tag, data, children 创建一个vnode
    function _createElement(
      context,
      tag,
      data,
      children,
      normalizationType
    ) {
      if (isDef(data) && isDef((data).__ob__)) {
         warn(
          "Avoid using observed data object as vnode data: " + (JSON.stringify(data)) + "\n" +
          'Always create fresh vnode data objects in each render!',
          context
        );
        return createEmptyVNode()
      }
      // object syntax in v-bind
      if (isDef(data) && isDef(data.is)) {
        tag = data.is;
      }
      if (!tag) {
        // in case of component :is set to falsy value
        return createEmptyVNode()
      }
      // warn against non-primitive key
      if (
        isDef(data) && isDef(data.key) && !isPrimitive(data.key)
      ) {
        {
          warn(
            'Avoid using non-primitive value as key, ' +
            'use string/number value instead.',
            context
          );
        }
      }
      // support single function children as default scoped slot
      if (Array.isArray(children) &&
        typeof children[0] === 'function'
      ) {
        data = data || {};
        data.scopedSlots = { default: children[0] };
        children.length = 0;
      }
      if (normalizationType === ALWAYS_NORMALIZE) {
        children = normalizeChildren(children);
      } else if (normalizationType === SIMPLE_NORMALIZE) {
        children = simpleNormalizeChildren(children);
      }
      var vnode, ns;
      if (typeof tag === 'string') {
        var Ctor;
        ns = (context.$vnode && context.$vnode.ns) || config.getTagNamespace(tag);
        if (config.isReservedTag(tag)) {
          // platform built-in elements
          if ( isDef(data) && isDef(data.nativeOn)) {
            warn(
              ("The .native modifier for v-on is only valid on components but it was used on <" + tag + ">."),
              context
            );
          }
          vnode = new VNode(
            config.parsePlatformTagName(tag), data, children,
            undefined, undefined, context
          );
        } else if ((!data || !data.pre) && isDef(Ctor = resolveAsset(context.$options, 'components', tag))) {
          // component
          vnode = createComponent(Ctor, data, context, children, tag);
        } else {
          // unknown or unlisted namespaced elements
          // check at runtime because it may get assigned a namespace when its
          // parent normalizes children
          vnode = new VNode(
            tag, data, children,
            undefined, undefined, context
          );
        }
      } else {
        // direct component options / constructor
        vnode = createComponent(tag, data, context, children);
      }
      if (Array.isArray(vnode)) {
        return vnode
      } else if (isDef(vnode)) {
        if (isDef(ns)) { applyNS(vnode, ns); }
        if (isDef(data)) { registerDeepBindings(data); }
        return vnode
      } else {
        return createEmptyVNode()
      }
    }
  
    function applyNS(vnode, ns, force) {
      vnode.ns = ns;
      if (vnode.tag === 'foreignObject') {
        // use default namespace inside foreignObject
        ns = undefined;
        force = true;
      }
      if (isDef(vnode.children)) {
        for (var i = 0, l = vnode.children.length; i < l; i++) {
          var child = vnode.children[i];
          if (isDef(child.tag) && (
            isUndef(child.ns) || (isTrue(force) && child.tag !== 'svg'))) {
            applyNS(child, ns, force);
          }
        }
      }
    }
  
    // ref #5318
    // necessary to ensure parent re-render when deep bindings like :style and
    // :class are used on slot nodes
    function registerDeepBindings(data) {
      if (isObject(data.style)) {
        traverse(data.style);
      }
      if (isObject(data.class)) {
        traverse(data.class);
      }
    }
  
    /*  */
  
    function initRender (vm) {
      vm._vnode = null; // the root of the child tree
      vm._staticTrees = null; // v-once cached trees
      var options = vm.$options;
      var parentVnode = vm.$vnode = options._parentVnode; // the placeholder node in parent tree
      var renderContext = parentVnode && parentVnode.context;
      vm.$slots = resolveSlots(options._renderChildren, renderContext);
      vm.$scopedSlots = emptyObject;
      // bind the createElement fn to this instance
      // so that we get proper render context inside it.
      // args order: tag, data, children, normalizationType, alwaysNormalize
      // internal version is used by render functions compiled from templates
      vm._c = function (a, b, c, d) { return createElement(vm, a, b, c, d, false); };
      // normalization is always applied for the public version, used in
      // user-written render functions.
      vm.$createElement = function (a, b, c, d) { return createElement(vm, a, b, c, d, true); };
  
      // $attrs & $listeners are exposed for easier HOC creation.
      // they need to be reactive so that HOCs using them are always updated
      var parentData = parentVnode && parentVnode.data;
  
      /* istanbul ignore else */
      {
        defineReactive(vm, '$attrs', parentData && parentData.attrs || emptyObject, function () {
          !isUpdatingChildComponent && warn("$attrs is readonly.", vm);
        }, true);
        defineReactive(vm, '$listeners', options._parentListeners || emptyObject, function () {
          !isUpdatingChildComponent && warn("$listeners is readonly.", vm);
        }, true);
      }
    }
  
    var currentRenderingInstance = null;
  
    function renderMixin (Vue) {
      // install runtime convenience helpers
      installRenderHelpers(Vue.prototype);
  
      Vue.prototype.$nextTick = function (fn) {
        return nextTick(fn, this)
      };
  
      Vue.prototype._render = function () {
        var vm = this;
        var ref = vm.$options;
        var render = ref.render;
        var _parentVnode = ref._parentVnode;
  
        if (_parentVnode) {
          vm.$scopedSlots = normalizeScopedSlots(
            _parentVnode.data.scopedSlots,
            vm.$slots,
            vm.$scopedSlots
          );
        }
  
        // set parent vnode. this allows render functions to have access
        // to the data on the placeholder node.
        vm.$vnode = _parentVnode;
        // render self
        var vnode;
        try {
          // There's no need to maintain a stack because all render fns are called
          // separately from one another. Nested component's render fns are called
          // when parent component is patched.
          currentRenderingInstance = vm;
          vnode = render.call(vm._renderProxy, vm.$createElement);
        } catch (e) {
          handleError(e, vm, "render");
          // return error render result,
          // or previous vnode to prevent render error causing blank component
          /* istanbul ignore else */
          if ( vm.$options.renderError) {
            try {
              vnode = vm.$options.renderError.call(vm._renderProxy, vm.$createElement, e);
            } catch (e) {
              handleError(e, vm, "renderError");
              vnode = vm._vnode;
            }
          } else {
            vnode = vm._vnode;
          }
        } finally {
          currentRenderingInstance = null;
        }
        // if the returned array contains only a single node, allow it
        if (Array.isArray(vnode) && vnode.length === 1) {
          vnode = vnode[0];
        }
        // return empty vnode in case the render function errored out
        if (!(vnode instanceof VNode)) {
          if ( Array.isArray(vnode)) {
            warn(
              'Multiple root nodes returned from render function. Render function ' +
              'should return a single root node.',
              vm
            );
          }
          vnode = createEmptyVNode();
        }
        // set parent
        vnode.parent = _parentVnode;
        return vnode
      };
    }
  
    /*  */
  
    function ensureCtor (comp, base) {
      if (
        comp.__esModule ||
        (hasSymbol && comp[Symbol.toStringTag] === 'Module')
      ) {
        comp = comp.default;
      }
      return isObject(comp)
        ? base.extend(comp)
        : comp
    }
  
    function createAsyncPlaceholder (
      factory,
      data,
      context,
      children,
      tag
    ) {
      var node = createEmptyVNode();
      node.asyncFactory = factory;
      node.asyncMeta = { data: data, context: context, children: children, tag: tag };
      return node
    }
  
    function resolveAsyncComponent (
      factory,
      baseCtor
    ) {
      if (isTrue(factory.error) && isDef(factory.errorComp)) {
        return factory.errorComp
      }
  
      if (isDef(factory.resolved)) {
        return factory.resolved
      }
  
      var owner = currentRenderingInstance;
      if (owner && isDef(factory.owners) && factory.owners.indexOf(owner) === -1) {
        // already pending
        factory.owners.push(owner);
      }
  
      if (isTrue(factory.loading) && isDef(factory.loadingComp)) {
        return factory.loadingComp
      }
  
      if (owner && !isDef(factory.owners)) {
        var owners = factory.owners = [owner];
        var sync = true;
        var timerLoading = null;
        var timerTimeout = null
  
        ;(owner).$on('hook:destroyed', function () { return remove(owners, owner); });
  
        var forceRender = function (renderCompleted) {
          for (var i = 0, l = owners.length; i < l; i++) {
            (owners[i]).$forceUpdate();
          }
  
          if (renderCompleted) {
            owners.length = 0;
            if (timerLoading !== null) {
              clearTimeout(timerLoading);
              timerLoading = null;
            }
            if (timerTimeout !== null) {
              clearTimeout(timerTimeout);
              timerTimeout = null;
            }
          }
        };
  
        var resolve = once(function (res) {
          // cache resolved
          factory.resolved = ensureCtor(res, baseCtor);
          // invoke callbacks only if this is not a synchronous resolve
          // (async resolves are shimmed as synchronous during SSR)
          if (!sync) {
            forceRender(true);
          } else {
            owners.length = 0;
          }
        });
  
        var reject = once(function (reason) {
           warn(
            "Failed to resolve async component: " + (String(factory)) +
            (reason ? ("\nReason: " + reason) : '')
          );
          if (isDef(factory.errorComp)) {
            factory.error = true;
            forceRender(true);
          }
        });
  
        var res = factory(resolve, reject);
  
        if (isObject(res)) {
          if (isPromise(res)) {
            // () => Promise
            if (isUndef(factory.resolved)) {
              res.then(resolve, reject);
            }
          } else if (isPromise(res.component)) {
            res.component.then(resolve, reject);
  
            if (isDef(res.error)) {
              factory.errorComp = ensureCtor(res.error, baseCtor);
            }
  
            if (isDef(res.loading)) {
              factory.loadingComp = ensureCtor(res.loading, baseCtor);
              if (res.delay === 0) {
                factory.loading = true;
              } else {
                timerLoading = setTimeout(function () {
                  timerLoading = null;
                  if (isUndef(factory.resolved) && isUndef(factory.error)) {
                    factory.loading = true;
                    forceRender(false);
                  }
                }, res.delay || 200);
              }
            }
  
            if (isDef(res.timeout)) {
              timerTimeout = setTimeout(function () {
                timerTimeout = null;
                if (isUndef(factory.resolved)) {
                  reject(
                     ("timeout (" + (res.timeout) + "ms)")
                      
                  );
                }
              }, res.timeout);
            }
          }
        }
  
        sync = false;
        // return in case resolved synchronously
        return factory.loading
          ? factory.loadingComp
          : factory.resolved
      }
    }
  
    /*  */
  
    function isAsyncPlaceholder (node) {
      return node.isComment && node.asyncFactory
    }
  
    /*  */
  
    function getFirstComponentChild (children) {
      if (Array.isArray(children)) {
        for (var i = 0; i < children.length; i++) {
          var c = children[i];
          if (isDef(c) && (isDef(c.componentOptions) || isAsyncPlaceholder(c))) {
            return c
          }
        }
      }
    }
  
    /*  */
  
    function initEvents (vm) {
      vm._events = Object.create(null);
      vm._hasHookEvent = false;
      // init parent attached events
      var listeners = vm.$options._parentListeners;
      if (listeners) {
        updateComponentListeners(vm, listeners);
      }
    }
  
    var target;
  
    function add (event, fn) {
      target.$on(event, fn);
    }
  
    function remove$1 (event, fn) {
      target.$off(event, fn);
    }
  
    function createOnceHandler (event, fn) {
      var _target = target;
      return function onceHandler () {
        var res = fn.apply(null, arguments);
        if (res !== null) {
          _target.$off(event, onceHandler);
        }
      }
    }
  
    function updateComponentListeners (
      vm,
      listeners,
      oldListeners
    ) {
      target = vm;
      updateListeners(listeners, oldListeners || {}, add, remove$1, createOnceHandler, vm);
      target = undefined;
    }
  
    function eventsMixin (Vue) {
      var hookRE = /^hook:/;
      Vue.prototype.$on = function (event, fn) {
        var vm = this;
        if (Array.isArray(event)) {
          for (var i = 0, l = event.length; i < l; i++) {
            vm.$on(event[i], fn);
          }
        } else {
          (vm._events[event] || (vm._events[event] = [])).push(fn);
          // optimize hook:event cost by using a boolean flag marked at registration
          // instead of a hash lookup
          if (hookRE.test(event)) {
            vm._hasHookEvent = true;
          }
        }
        return vm
      };
  
      Vue.prototype.$once = function (event, fn) {
        var vm = this;
        function on () {
          vm.$off(event, on);
          fn.apply(vm, arguments);
        }
        on.fn = fn;
        vm.$on(event, on);
        return vm
      };
  
      Vue.prototype.$off = function (event, fn) {
        var vm = this;
        // all
        if (!arguments.length) {
          vm._events = Object.create(null);
          return vm
        }
        // array of events
        if (Array.isArray(event)) {
          for (var i$1 = 0, l = event.length; i$1 < l; i$1++) {
            vm.$off(event[i$1], fn);
          }
          return vm
        }
        // specific event
        var cbs = vm._events[event];
        if (!cbs) {
          return vm
        }
        if (!fn) {
          vm._events[event] = null;
          return vm
        }
        // specific handler
        var cb;
        var i = cbs.length;
        while (i--) {
          cb = cbs[i];
          if (cb === fn || cb.fn === fn) {
            cbs.splice(i, 1);
            break
          }
        }
        return vm
      };
  
      Vue.prototype.$emit = function (event) {
        var vm = this;
        {
          var lowerCaseEvent = event.toLowerCase();
          if (lowerCaseEvent !== event && vm._events[lowerCaseEvent]) {
            tip(
              "Event \"" + lowerCaseEvent + "\" is emitted in component " +
              (formatComponentName(vm)) + " but the handler is registered for \"" + event + "\". " +
              "Note that HTML attributes are case-insensitive and you cannot use " +
              "v-on to listen to camelCase events when using in-DOM templates. " +
              "You should probably use \"" + (hyphenate(event)) + "\" instead of \"" + event + "\"."
            );
          }
        }
        var cbs = vm._events[event];
        if (cbs) {
          cbs = cbs.length > 1 ? toArray(cbs) : cbs;
          var args = toArray(arguments, 1);
          var info = "event handler for \"" + event + "\"";
          for (var i = 0, l = cbs.length; i < l; i++) {
            invokeWithErrorHandling(cbs[i], vm, args, vm, info);
          }
        }
        return vm
      };
    }
  
    /*  */
  
    var activeInstance = null;
    var isUpdatingChildComponent = false;
  
    function setActiveInstance(vm) {
      var prevActiveInstance = activeInstance;
      activeInstance = vm;
      return function () {
        activeInstance = prevActiveInstance;
      }
    }
  
    function initLifecycle (vm) {
      var options = vm.$options;
  
      // locate first non-abstract parent
      var parent = options.parent;
      if (parent && !options.abstract) {
        while (parent.$options.abstract && parent.$parent) {
          parent = parent.$parent;
        }
        parent.$children.push(vm);
      }
  
      vm.$parent = parent;
      vm.$root = parent ? parent.$root : vm;
  
      vm.$children = [];
      vm.$refs = {};
  
      vm._watcher = null;
      vm._inactive = null;
      vm._directInactive = false;
      vm._isMounted = false;
      vm._isDestroyed = false;
      vm._isBeingDestroyed = false;
    }
  
    function lifecycleMixin (Vue) {
      Vue.prototype._update = function (vnode, hydrating) {
        var vm = this;
        var prevEl = vm.$el;
        var prevVnode = vm._vnode;
        var restoreActiveInstance = setActiveInstance(vm);
        vm._vnode = vnode;
        // Vue.prototype.__patch__ is injected in entry points
        // based on the rendering backend used.
        if (!prevVnode) {
          // initial render
          vm.$el = vm.__patch__(vm.$el, vnode, hydrating, false /* removeOnly */);
        } else {
          // updates
          vm.$el = vm.__patch__(prevVnode, vnode);
        }
        restoreActiveInstance();
        // update __vue__ reference
        if (prevEl) {
          prevEl.__vue__ = null;
        }
        if (vm.$el) {
          vm.$el.__vue__ = vm;
        }
        // if parent is an HOC, update its $el as well
        if (vm.$vnode && vm.$parent && vm.$vnode === vm.$parent._vnode) {
          vm.$parent.$el = vm.$el;
        }
        // updated hook is called by the scheduler to ensure that children are
        // updated in a parent's updated hook.
      };
  
      Vue.prototype.$forceUpdate = function () {
        var vm = this;
        if (vm._watcher) {
          vm._watcher.update();
        }
      };
  
      Vue.prototype.$destroy = function () {
        var vm = this;
        if (vm._isBeingDestroyed) {
          return
        }
        callHook(vm, 'beforeDestroy');
        vm._isBeingDestroyed = true;
        // remove self from parent
        var parent = vm.$parent;
        if (parent && !parent._isBeingDestroyed && !vm.$options.abstract) {
          remove(parent.$children, vm);
        }
        // teardown watchers
        if (vm._watcher) {
          vm._watcher.teardown();
        }
        var i = vm._watchers.length;
        while (i--) {
          vm._watchers[i].teardown();
        }
        // remove reference from data ob
        // frozen object may not have observer.
        if (vm._data.__ob__) {
          vm._data.__ob__.vmCount--;
        }
        // call the last hook...
        vm._isDestroyed = true;
        // invoke destroy hooks on current rendered tree
        vm.__patch__(vm._vnode, null);
        // fire destroyed hook
        callHook(vm, 'destroyed');
        // turn off all instance listeners.
        vm.$off();
        // remove __vue__ reference
        if (vm.$el) {
          vm.$el.__vue__ = null;
        }
        // release circular reference (#6759)
        if (vm.$vnode) {
          vm.$vnode.parent = null;
        }
      };
    }
  
    function mountComponent (
      vm,
      el,
      hydrating
    ) {
      vm.$el = el;
      if (!vm.$options.render) {
        vm.$options.render = createEmptyVNode;
        {
          /* istanbul ignore if */
          if ((vm.$options.template && vm.$options.template.charAt(0) !== '#') ||
            vm.$options.el || el) {
            warn(
              'You are using the runtime-only build of Vue where the template ' +
              'compiler is not available. Either pre-compile the templates into ' +
              'render functions, or use the compiler-included build.',
              vm
            );
          } else {
            warn(
              'Failed to mount component: template or render function not defined.',
              vm
            );
          }
        }
      }
      callHook(vm, 'beforeMount');
  
      var updateComponent;
      /* istanbul ignore if */
      if ( config.performance && mark) {
        updateComponent = function () {
          var name = vm._name;
          var id = vm._uid;
          var startTag = "vue-perf-start:" + id;
          var endTag = "vue-perf-end:" + id;
  
          mark(startTag);
          var vnode = vm._render();
          mark(endTag);
          measure(("vue " + name + " render"), startTag, endTag);
  
          mark(startTag);
          vm._update(vnode, hydrating);
          mark(endTag);
          measure(("vue " + name + " patch"), startTag, endTag);
        };
      } else {
        updateComponent = function () {
          vm._update(vm._render(), hydrating);
        };
      }
  
      // we set this to vm._watcher inside the watcher's constructor
      // since the watcher's initial patch may call $forceUpdate (e.g. inside child
      // component's mounted hook), which relies on vm._watcher being already defined
      new Watcher(vm, updateComponent, noop, {
        before: function before () {
          if (vm._isMounted && !vm._isDestroyed) {
            callHook(vm, 'beforeUpdate');
          }
        }
      }, true /* isRenderWatcher */);
      hydrating = false;
  
      // manually mounted instance, call mounted on self
      // mounted is called for render-created child components in its inserted hook
      if (vm.$vnode == null) {
        vm._isMounted = true;
        callHook(vm, 'mounted');
      }
      return vm
    }
  
    function updateChildComponent (
      vm,
      propsData,
      listeners,
      parentVnode,
      renderChildren
    ) {
      {
        isUpdatingChildComponent = true;
      }
  
      // determine whether component has slot children
      // we need to do this before overwriting $options._renderChildren.
  
      // check if there are dynamic scopedSlots (hand-written or compiled but with
      // dynamic slot names). Static scoped slots compiled from template has the
      // "$stable" marker.
      var newScopedSlots = parentVnode.data.scopedSlots;
      var oldScopedSlots = vm.$scopedSlots;
      var hasDynamicScopedSlot = !!(
        (newScopedSlots && !newScopedSlots.$stable) ||
        (oldScopedSlots !== emptyObject && !oldScopedSlots.$stable) ||
        (newScopedSlots && vm.$scopedSlots.$key !== newScopedSlots.$key)
      );
  
      // Any static slot children from the parent may have changed during parent's
      // update. Dynamic scoped slots may also have changed. In such cases, a forced
      // update is necessary to ensure correctness.
      var needsForceUpdate = !!(
        renderChildren ||               // has new static slots
        vm.$options._renderChildren ||  // has old static slots
        hasDynamicScopedSlot
      );
  
      vm.$options._parentVnode = parentVnode;
      vm.$vnode = parentVnode; // update vm's placeholder node without re-render
  
      if (vm._vnode) { // update child tree's parent
        vm._vnode.parent = parentVnode;
      }
      vm.$options._renderChildren = renderChildren;
  
      // update $attrs and $listeners hash
      // these are also reactive so they may trigger child update if the child
      // used them during render
      vm.$attrs = parentVnode.data.attrs || emptyObject;
      vm.$listeners = listeners || emptyObject;
  
      // update props
      if (propsData && vm.$options.props) {
        toggleObserving(false);
        var props = vm._props;
        var propKeys = vm.$options._propKeys || [];
        for (var i = 0; i < propKeys.length; i++) {
          var key = propKeys[i];
          var propOptions = vm.$options.props; // wtf flow?
          props[key] = validateProp(key, propOptions, propsData, vm);
        }
        toggleObserving(true);
        // keep a copy of raw propsData
        vm.$options.propsData = propsData;
      }
  
      // update listeners
      listeners = listeners || emptyObject;
      var oldListeners = vm.$options._parentListeners;
      vm.$options._parentListeners = listeners;
      updateComponentListeners(vm, listeners, oldListeners);
  
      // resolve slots + force update if has children
      if (needsForceUpdate) {
        vm.$slots = resolveSlots(renderChildren, parentVnode.context);
        vm.$forceUpdate();
      }
  
      {
        isUpdatingChildComponent = false;
      }
    }
  
    function isInInactiveTree (vm) {
      while (vm && (vm = vm.$parent)) {
        if (vm._inactive) { return true }
      }
      return false
    }
  
    function activateChildComponent (vm, direct) {
      if (direct) {
        vm._directInactive = false;
        if (isInInactiveTree(vm)) {
          return
        }
      } else if (vm._directInactive) {
        return
      }
      if (vm._inactive || vm._inactive === null) {
        vm._inactive = false;
        for (var i = 0; i < vm.$children.length; i++) {
          activateChildComponent(vm.$children[i]);
        }
        callHook(vm, 'activated');
      }
    }
  
    function deactivateChildComponent (vm, direct) {
      if (direct) {
        vm._directInactive = true;
        if (isInInactiveTree(vm)) {
          return
        }
      }
      if (!vm._inactive) {
        vm._inactive = true;
        for (var i = 0; i < vm.$children.length; i++) {
          deactivateChildComponent(vm.$children[i]);
        }
        callHook(vm, 'deactivated');
      }
    }
  
    function callHook (vm, hook) {
      // #7573 disable dep collection when invoking lifecycle hooks
      pushTarget();
      var handlers = vm.$options[hook];
      var info = hook + " hook";
      if (handlers) {
        for (var i = 0, j = handlers.length; i < j; i++) {
          invokeWithErrorHandling(handlers[i], vm, null, vm, info);
        }
      }
      if (vm._hasHookEvent) {
        vm.$emit('hook:' + hook);
      }
      popTarget();
    }
  
    /*  */
  
    var MAX_UPDATE_COUNT = 100;
  
    var queue = [];
    var activatedChildren = [];
    var has = {};
    var circular = {};
    var waiting = false;
    var flushing = false;
    var index = 0;
  
    /**
     * Reset the scheduler's state.
     */
    function resetSchedulerState() {
      index = queue.length = activatedChildren.length = 0;
      has = {};
      {
        circular = {};
      }
      waiting = flushing = false;
    }
  
    // Async edge case #6566 requires saving the timestamp when event listeners are
    // attached. However, calling performance.now() has a perf overhead especially
    // if the page has thousands of event listeners. Instead, we take a timestamp
    // every time the scheduler flushes and use that for all event listeners
    // attached during that flush.
    var currentFlushTimestamp = 0;
  
    // Async edge case fix requires storing an event listener's attach timestamp.
    var getNow = Date.now;
  
    // Determine what event timestamp the browser is using. Annoyingly, the
    // timestamp can either be hi-res (relative to page load) or low-res
    // (relative to UNIX epoch), so in order to compare time we have to use the
    // same timestamp type when saving the flush timestamp.
    // All IE versions use low-res event timestamps, and have problematic clock
    // implementations (#9632)
    if (inBrowser && !isIE) {
      var performance = window.performance;
      if (
        performance &&
        typeof performance.now === 'function' &&
        getNow() > document.createEvent('Event').timeStamp
      ) {
        // if the event timestamp, although evaluated AFTER the Date.now(), is
        // smaller than it, it means the event is using a hi-res timestamp,
        // and we need to use the hi-res version for event listener timestamps as
        // well.
        getNow = function () { return performance.now(); };
      }
    }
  
    /**
     * Flush both queues and run the watchers.
     */
    function flushSchedulerQueue() {
      currentFlushTimestamp = getNow();
      flushing = true;
      var watcher, id;
  
      // Sort queue before flush.
      // This ensures that:
      // 1. Components are updated from parent to child. (because parent is always
      //    created before the child)
      // 2. A component's user watchers are run before its render watcher (because
      //    user watchers are created before the render watcher)
      // 3. If a component is destroyed during a parent component's watcher run,
      //    its watchers can be skipped.
      queue.sort(function (a, b) { return a.id - b.id; });
  
      // do not cache length because more watchers might be pushed
      // as we run existing watchers
      for (index = 0; index < queue.length; index++) {
        watcher = queue[index];
        if (watcher.before) {
          watcher.before();
        }
        id = watcher.id;
        has[id] = null;
        watcher.run();
        // in dev build, check and stop circular updates.
        if ( has[id] != null) {
          circular[id] = (circular[id] || 0) + 1;
          if (circular[id] > MAX_UPDATE_COUNT) {
            warn(
              'You may have an infinite update loop ' + (
                watcher.user
                  ? ("in watcher with expression \"" + (watcher.expression) + "\"")
                  : "in a component render function."
              ),
              watcher.vm
            );
            break
          }
        }
      }
  
      // keep copies of post queues before resetting state
      var activatedQueue = activatedChildren.slice();
      var updatedQueue = queue.slice();
  
      resetSchedulerState();
  
      // call component updated and activated hooks
      callActivatedHooks(activatedQueue);
      callUpdatedHooks(updatedQueue);
  
      // devtool hook
      /* istanbul ignore if */
      if (devtools && config.devtools) {
        devtools.emit('flush');
      }
    }
  
    function callUpdatedHooks(queue) {
      var i = queue.length;
      while (i--) {
        var watcher = queue[i];
        var vm = watcher.vm;
        if (vm._watcher === watcher && vm._isMounted && !vm._isDestroyed) {
          callHook(vm, 'updated');
        }
      }
    }
  
    /**
     * Queue a kept-alive component that was activated during patch.
     * The queue will be processed after the entire tree has been patched.
     */
    function queueActivatedComponent(vm) {
      // setting _inactive to false here so that a render function can
      // rely on checking whether it's in an inactive tree (e.g. router-view)
      vm._inactive = false;
      activatedChildren.push(vm);
    }
  
    function callActivatedHooks(queue) {
      for (var i = 0; i < queue.length; i++) {
        queue[i]._inactive = true;
        activateChildComponent(queue[i], true /* true */);
      }
    }
  
    /**
     * Push a watcher into the watcher queue.
     * Jobs with duplicate IDs will be skipped unless it's
     * pushed when the queue is being flushed.
     */
    function queueWatcher(watcher) {
      // 获取watcher 的id
      var id = watcher.id;
      // 判断是否已经入队， 去重
      if (has[id] == null) {
        has[id] = true;
        if (!flushing) {
          // push 入队   queue 任务队列
          queue.push(watcher);
        } else {
          // if already flushing, splice the watcher based on its id
          // if already past its id, it will be run next immediately.
          var i = queue.length - 1;
          while (i > index && queue[i].id > watcher.id) {
            i--;
          }
          queue.splice(i + 1, 0, watcher);
        }
        // queue the flush
        if (!waiting) {
          waiting = true;
  
          if ( !config.async) {
            flushSchedulerQueue();
            return
          }
          // 如果没有在等待状态
          // 使用nextTick 将flushSchedulerQueue 入队
          // 尝试异步方式将该函数放入微任务队列中
          nextTick(flushSchedulerQueue);
        }
      }
    }
  
    /*  */
  
  
  
    var uid$1 = 0;
  
    /**
     * A watcher parses an expression, collects dependencies,
     * and fires callback when the expression value changes.
     * This is used for both the $watch() api and directives.
     */
    var Watcher = function Watcher(
      vm,
      expOrFn,
      cb,
      options,
      isRenderWatcher
    ) {
      this.vm = vm;
      if (isRenderWatcher) {
        vm._watcher = this;
      }
      vm._watchers.push(this);
      // options
      if (options) {
        this.deep = !!options.deep;
        this.user = !!options.user;
        this.lazy = !!options.lazy;
        this.sync = !!options.sync;
        this.before = options.before;
      } else {
        this.deep = this.user = this.lazy = this.sync = false;
      }
      this.cb = cb;
      this.id = ++uid$1; // uid for batching
      this.active = true;
      this.dirty = this.lazy; // for lazy watchers
      this.deps = [];
      this.newDeps = [];
      this.depIds = new _Set();
      this.newDepIds = new _Set();
      this.expression =  expOrFn.toString()
        ;
      // parse expression for getter
      if (typeof expOrFn === 'function') {
        this.getter = expOrFn;
      } else {
        this.getter = parsePath(expOrFn);
        if (!this.getter) {
          this.getter = noop;
           warn(
            "Failed watching path: \"" + expOrFn + "\" " +
            'Watcher only accepts simple dot-delimited paths. ' +
            'For full control, use a function instead.',
            vm
          );
        }
      }
      this.value = this.lazy
        ? undefined
        : this.get();
    };
  
    /**
     * Evaluate the getter, and re-collect dependencies.
     */
    Watcher.prototype.get = function get () {
      pushTarget(this);
      var value;
      var vm = this.vm;
      try {
        value = this.getter.call(vm, vm);
      } catch (e) {
        if (this.user) {
          handleError(e, vm, ("getter for watcher \"" + (this.expression) + "\""));
        } else {
          throw e
        }
      } finally {
        // "touch" every property so they are all tracked as
        // dependencies for deep watching
        if (this.deep) {
          traverse(value);
        }
        popTarget();
        this.cleanupDeps();
      }
      return value
    };
  
    /**
     * Add a dependency to this directive.
     */
    Watcher.prototype.addDep = function addDep (dep) {
      var id = dep.id;
      if (!this.newDepIds.has(id)) {
        this.newDepIds.add(id);
        this.newDeps.push(dep);
        if (!this.depIds.has(id)) {
          dep.addSub(this);
        }
      }
    };
  
    /**
     * Clean up for dependency collection.
     */
    Watcher.prototype.cleanupDeps = function cleanupDeps () {
      var i = this.deps.length;
      while (i--) {
        var dep = this.deps[i];
        if (!this.newDepIds.has(dep.id)) {
          dep.removeSub(this);
        }
      }
      var tmp = this.depIds;
      this.depIds = this.newDepIds;
      this.newDepIds = tmp;
      this.newDepIds.clear();
      tmp = this.deps;
      this.deps = this.newDeps;
      this.newDeps = tmp;
      this.newDeps.length = 0;
    };
  
    /**
     * Subscriber interface.
     * Will be called when a dependency changes.
     */
    Watcher.prototype.update = function update () {
      /* istanbul ignore else */
      if (this.lazy) {
        this.dirty = true;
      } else if (this.sync) {
        this.run();
      } else {
        // watcher 入队
        queueWatcher(this);
      }
    };
  
    /**
     * Scheduler job interface.
     * Will be called by the scheduler.
     */
    Watcher.prototype.run = function run () {
      if (this.active) {
        var value = this.get();
        if (
          value !== this.value ||
          // Deep watchers and watchers on Object/Arrays should fire even
          // when the value is the same, because the value may
          // have mutated.
          isObject(value) ||
          this.deep
        ) {
          // set new value
          var oldValue = this.value;
          this.value = value;
          if (this.user) {
            try {
              this.cb.call(this.vm, value, oldValue);
            } catch (e) {
              handleError(e, this.vm, ("callback for watcher \"" + (this.expression) + "\""));
            }
          } else {
            this.cb.call(this.vm, value, oldValue);
          }
        }
      }
    };
  
    /**
     * Evaluate the value of the watcher.
     * This only gets called for lazy watchers.
     */
    Watcher.prototype.evaluate = function evaluate () {
      this.value = this.get();
      this.dirty = false;
    };
  
    /**
     * Depend on all deps collected by this watcher.
     */
    Watcher.prototype.depend = function depend () {
      var i = this.deps.length;
      while (i--) {
        this.deps[i].depend();
      }
    };
  
    /**
     * Remove self from all dependencies' subscriber list.
     */
    Watcher.prototype.teardown = function teardown () {
      if (this.active) {
        // remove self from vm's watcher list
        // this is a somewhat expensive operation so we skip it
        // if the vm is being destroyed.
        if (!this.vm._isBeingDestroyed) {
          remove(this.vm._watchers, this);
        }
        var i = this.deps.length;
        while (i--) {
          this.deps[i].removeSub(this);
        }
        this.active = false;
      }
    };
  
    /*  */
  
    var sharedPropertyDefinition = {
      enumerable: true,
      configurable: true,
      get: noop,
      set: noop
    };
  
    function proxy (target, sourceKey, key) {
      sharedPropertyDefinition.get = function proxyGetter () {
        return this[sourceKey][key]
      };
      sharedPropertyDefinition.set = function proxySetter (val) {
        this[sourceKey][key] = val;
      };
      Object.defineProperty(target, key, sharedPropertyDefinition);
    }
  
    function initState (vm) {
      vm._watchers = [];
      var opts = vm.$options;
      if (opts.props) { initProps(vm, opts.props); }
      if (opts.methods) { initMethods(vm, opts.methods); }
      if (opts.data) {
        initData(vm);
      } else {
        observe(vm._data = {}, true /* asRootData */);
      }
      if (opts.computed) { initComputed(vm, opts.computed); }
      if (opts.watch && opts.watch !== nativeWatch) {
        initWatch(vm, opts.watch);
      }
    }
  
    function initProps (vm, propsOptions) {
      var propsData = vm.$options.propsData || {};
      var props = vm._props = {};
      // cache prop keys so that future props updates can iterate using Array
      // instead of dynamic object key enumeration.
      var keys = vm.$options._propKeys = [];
      var isRoot = !vm.$parent;
      // root instance props should be converted
      if (!isRoot) {
        toggleObserving(false);
      }
      var loop = function ( key ) {
        keys.push(key);
        var value = validateProp(key, propsOptions, propsData, vm);
        /* istanbul ignore else */
        {
          var hyphenatedKey = hyphenate(key);
          if (isReservedAttribute(hyphenatedKey) ||
              config.isReservedAttr(hyphenatedKey)) {
            warn(
              ("\"" + hyphenatedKey + "\" is a reserved attribute and cannot be used as component prop."),
              vm
            );
          }
          defineReactive(props, key, value, function () {
            if (!isRoot && !isUpdatingChildComponent) {
              warn(
                "Avoid mutating a prop directly since the value will be " +
                "overwritten whenever the parent component re-renders. " +
                "Instead, use a data or computed property based on the prop's " +
                "value. Prop being mutated: \"" + key + "\"",
                vm
              );
            }
          });
        }
        // static props are already proxied on the component's prototype
        // during Vue.extend(). We only need to proxy props defined at
        // instantiation here.
        if (!(key in vm)) {
          proxy(vm, "_props", key);
        }
      };
  
      for (var key in propsOptions) loop( key );
      toggleObserving(true);
    }
  
    function initData (vm) {
      var data = vm.$options.data;
      data = vm._data = typeof data === 'function'
        ? getData(data, vm)
        : data || {};
      if (!isPlainObject(data)) {
        data = {};
         warn(
          'data functions should return an object:\n' +
          'https://vuejs.org/v2/guide/components.html#data-Must-Be-a-Function',
          vm
        );
      }
      // proxy data on instance
      var keys = Object.keys(data);
      var props = vm.$options.props;
      var methods = vm.$options.methods;
      var i = keys.length;
      while (i--) {
        var key = keys[i];
        {
          if (methods && hasOwn(methods, key)) {
            warn(
              ("Method \"" + key + "\" has already been defined as a data property."),
              vm
            );
          }
        }
        if (props && hasOwn(props, key)) {
           warn(
            "The data property \"" + key + "\" is already declared as a prop. " +
            "Use prop default value instead.",
            vm
          );
        } else if (!isReserved(key)) {
          proxy(vm, "_data", key);
        }
      }
      // observe data
      observe(data, true /* asRootData */);
    }
  
    function getData (data, vm) {
      // #7573 disable dep collection when invoking data getters
      pushTarget();
      try {
        return data.call(vm, vm)
      } catch (e) {
        handleError(e, vm, "data()");
        return {}
      } finally {
        popTarget();
      }
    }
  
    var computedWatcherOptions = { lazy: true };
  
    function initComputed (vm, computed) {
      // $flow-disable-line
      var watchers = vm._computedWatchers = Object.create(null);
      // computed properties are just getters during SSR
      var isSSR = isServerRendering();
  
      for (var key in computed) {
        var userDef = computed[key];
        var getter = typeof userDef === 'function' ? userDef : userDef.get;
        if ( getter == null) {
          warn(
            ("Getter is missing for computed property \"" + key + "\"."),
            vm
          );
        }
  
        if (!isSSR) {
          // create internal watcher for the computed property.
          watchers[key] = new Watcher(
            vm,
            getter || noop,
            noop,
            computedWatcherOptions
          );
        }
  
        // component-defined computed properties are already defined on the
        // component prototype. We only need to define computed properties defined
        // at instantiation here.
        if (!(key in vm)) {
          defineComputed(vm, key, userDef);
        } else {
          if (key in vm.$data) {
            warn(("The computed property \"" + key + "\" is already defined in data."), vm);
          } else if (vm.$options.props && key in vm.$options.props) {
            warn(("The computed property \"" + key + "\" is already defined as a prop."), vm);
          }
        }
      }
    }
  
    function defineComputed (
      target,
      key,
      userDef
    ) {
      var shouldCache = !isServerRendering();
      if (typeof userDef === 'function') {
        sharedPropertyDefinition.get = shouldCache
          ? createComputedGetter(key)
          : createGetterInvoker(userDef);
        sharedPropertyDefinition.set = noop;
      } else {
        sharedPropertyDefinition.get = userDef.get
          ? shouldCache && userDef.cache !== false
            ? createComputedGetter(key)
            : createGetterInvoker(userDef.get)
          : noop;
        sharedPropertyDefinition.set = userDef.set || noop;
      }
      if (
          sharedPropertyDefinition.set === noop) {
        sharedPropertyDefinition.set = function () {
          warn(
            ("Computed property \"" + key + "\" was assigned to but it has no setter."),
            this
          );
        };
      }
      Object.defineProperty(target, key, sharedPropertyDefinition);
    }
  
    function createComputedGetter (key) {
      return function computedGetter () {
        var watcher = this._computedWatchers && this._computedWatchers[key];
        if (watcher) {
          if (watcher.dirty) {
            watcher.evaluate();
          }
          if (Dep.target) {
            watcher.depend();
          }
          return watcher.value
        }
      }
    }
  
    function createGetterInvoker(fn) {
      return function computedGetter () {
        return fn.call(this, this)
      }
    }
  
    function initMethods (vm, methods) {
      var props = vm.$options.props;
      for (var key in methods) {
        {
          if (typeof methods[key] !== 'function') {
            warn(
              "Method \"" + key + "\" has type \"" + (typeof methods[key]) + "\" in the component definition. " +
              "Did you reference the function correctly?",
              vm
            );
          }
          if (props && hasOwn(props, key)) {
            warn(
              ("Method \"" + key + "\" has already been defined as a prop."),
              vm
            );
          }
          if ((key in vm) && isReserved(key)) {
            warn(
              "Method \"" + key + "\" conflicts with an existing Vue instance method. " +
              "Avoid defining component methods that start with _ or $."
            );
          }
        }
        vm[key] = typeof methods[key] !== 'function' ? noop : bind(methods[key], vm);
      }
    }
  
    function initWatch (vm, watch) {
      for (var key in watch) {
        var handler = watch[key];
        if (Array.isArray(handler)) {
          for (var i = 0; i < handler.length; i++) {
            createWatcher(vm, key, handler[i]);
          }
        } else {
          createWatcher(vm, key, handler);
        }
      }
    }
  
    function createWatcher (
      vm,
      expOrFn,
      handler,
      options
    ) {
      if (isPlainObject(handler)) {
        options = handler;
        handler = handler.handler;
      }
      if (typeof handler === 'string') {
        handler = vm[handler];
      }
      return vm.$watch(expOrFn, handler, options)
    }
  
    function stateMixin (Vue) {
      // flow somehow has problems with directly declared definition object
      // when using Object.defineProperty, so we have to procedurally build up
      // the object here.
      var dataDef = {};
      dataDef.get = function () { return this._data };
      var propsDef = {};
      propsDef.get = function () { return this._props };
      {
        dataDef.set = function () {
          warn(
            'Avoid replacing instance root $data. ' +
            'Use nested data properties instead.',
            this
          );
        };
        propsDef.set = function () {
          warn("$props is readonly.", this);
        };
      }
      Object.defineProperty(Vue.prototype, '$data', dataDef);
      Object.defineProperty(Vue.prototype, '$props', propsDef);
  
      Vue.prototype.$set = set;
      Vue.prototype.$delete = del;
  
      Vue.prototype.$watch = function (
        expOrFn,
        cb,
        options
      ) {
        var vm = this;
        if (isPlainObject(cb)) {
          return createWatcher(vm, expOrFn, cb, options)
        }
        options = options || {};
        options.user = true;
        var watcher = new Watcher(vm, expOrFn, cb, options);
        if (options.immediate) {
          try {
            cb.call(vm, watcher.value);
          } catch (error) {
            handleError(error, vm, ("callback for immediate watcher \"" + (watcher.expression) + "\""));
          }
        }
        return function unwatchFn () {
          watcher.teardown();
        }
      };
    }
  
    /*  */
  
    var uid$2 = 0;
  
    function initMixin(Vue) {
      // 扩展_init
      Vue.prototype._init = function (options) {
        var vm = this;
        // a uid
        vm._uid = uid$2++;
  
        var startTag, endTag;
        /* istanbul ignore if */
        if ( config.performance && mark) {
          startTag = "vue-perf-start:" + (vm._uid);
          endTag = "vue-perf-end:" + (vm._uid);
          mark(startTag);
        }
  
        // a flag to avoid this being observed
        vm._isVue = true;
        // merge options
        // 合并选项
        if (options && options._isComponent) {
          // optimize internal component instantiation
          // since dynamic options merging is pretty slow, and none of the
          // internal component options needs special treatment.
          initInternalComponent(vm, options);
        } else {
          vm.$options = mergeOptions(
            resolveConstructorOptions(vm.constructor),
            options || {},
            vm
          );
        }
        /* istanbul ignore else */
        {
          initProxy(vm);
        }
        // expose real self
  
        // 各种初始化
        vm._self = vm;
        initLifecycle(vm); // $parent/ $root/ $children
        initEvents(vm);  // 自定义事件监听
        initRender(vm);  // $slots/$createElement
        callHook(vm, 'beforeCreate');
        // 获取祖辈注入的数据
        initInjections(vm); // resolve injections before data/props
        initState(vm);  // 数据状态初始化： data/props/methods/computed/watch
        initProvide(vm); // resolve provide after data/props
        callHook(vm, 'created');
  
        /* istanbul ignore if */
        if ( config.performance && mark) {
          vm._name = formatComponentName(vm, false);
          mark(endTag);
          measure(("vue " + (vm._name) + " init"), startTag, endTag);
        }
  
        // 选项如果有el，自动执行$mount
        if (vm.$options.el) {
          vm.$mount(vm.$options.el);
        }
      };
    }
  
    function initInternalComponent(vm, options) {
      var opts = vm.$options = Object.create(vm.constructor.options);
      // doing this because it's faster than dynamic enumeration.
      var parentVnode = options._parentVnode;
      opts.parent = options.parent;
      opts._parentVnode = parentVnode;
  
      var vnodeComponentOptions = parentVnode.componentOptions;
      opts.propsData = vnodeComponentOptions.propsData;
      opts._parentListeners = vnodeComponentOptions.listeners;
      opts._renderChildren = vnodeComponentOptions.children;
      opts._componentTag = vnodeComponentOptions.tag;
  
      if (options.render) {
        opts.render = options.render;
        opts.staticRenderFns = options.staticRenderFns;
      }
    }
  
    function resolveConstructorOptions(Ctor) {
      var options = Ctor.options;
      if (Ctor.super) {
        var superOptions = resolveConstructorOptions(Ctor.super);
        var cachedSuperOptions = Ctor.superOptions;
        if (superOptions !== cachedSuperOptions) {
          // super option changed,
          // need to resolve new options.
          Ctor.superOptions = superOptions;
          // check if there are any late-modified/attached options (#4976)
          var modifiedOptions = resolveModifiedOptions(Ctor);
          // update base extend options
          if (modifiedOptions) {
            extend(Ctor.extendOptions, modifiedOptions);
          }
          options = Ctor.options = mergeOptions(superOptions, Ctor.extendOptions);
          if (options.name) {
            options.components[options.name] = Ctor;
          }
        }
      }
      return options
    }
  
    function resolveModifiedOptions(Ctor) {
      var modified;
      var latest = Ctor.options;
      var sealed = Ctor.sealedOptions;
      for (var key in latest) {
        if (latest[key] !== sealed[key]) {
          if (!modified) { modified = {}; }
          modified[key] = latest[key];
        }
      }
      return modified
    }
  
    // Vue构造函数
    function Vue(options) {
      if (
        !(this instanceof Vue)
      ) {
        warn('Vue is a constructor and should be called with the `new` keyword');
      }
      // 执行初始化 _init
      this._init(options);
    }
  
    initMixin(Vue); // 扩展了一个_init方法
    stateMixin(Vue); // $data/ $props/ $set/ $delete/ $watch
    eventsMixin(Vue); // $on /$emit/ $once /$off
    lifecycleMixin(Vue); // _update/ $forceUpdate  / $destory
    renderMixin(Vue); // $nextTick / _render
  
    /*  */
  
    function initUse (Vue) {
      Vue.use = function (plugin) {
        var installedPlugins = (this._installedPlugins || (this._installedPlugins = []));
        if (installedPlugins.indexOf(plugin) > -1) {
          return this
        }
  
        // additional parameters
        var args = toArray(arguments, 1);
        args.unshift(this);
        if (typeof plugin.install === 'function') {
          plugin.install.apply(plugin, args);
        } else if (typeof plugin === 'function') {
          plugin.apply(null, args);
        }
        installedPlugins.push(plugin);
        return this
      };
    }
  
    /*  */
  
    function initMixin$1 (Vue) {
      Vue.mixin = function (mixin) {
        this.options = mergeOptions(this.options, mixin);
        return this
      };
    }
  
    /*  */
  
    function initExtend (Vue) {
      /**
       * Each instance constructor, including Vue, has a unique
       * cid. This enables us to create wrapped "child
       * constructors" for prototypal inheritance and cache them.
       */
      Vue.cid = 0;
      var cid = 1;
  
      /**
       * Class inheritance
       */
      Vue.extend = function (extendOptions) {
        extendOptions = extendOptions || {};
        var Super = this;
        var SuperId = Super.cid;
        var cachedCtors = extendOptions._Ctor || (extendOptions._Ctor = {});
        if (cachedCtors[SuperId]) {
          return cachedCtors[SuperId]
        }
  
        var name = extendOptions.name || Super.options.name;
        if ( name) {
          validateComponentName(name);
        }
  
        var Sub = function VueComponent (options) {
          this._init(options);
        };
        Sub.prototype = Object.create(Super.prototype);
        Sub.prototype.constructor = Sub;
        Sub.cid = cid++;
        Sub.options = mergeOptions(
          Super.options,
          extendOptions
        );
        Sub['super'] = Super;
  
        // For props and computed properties, we define the proxy getters on
        // the Vue instances at extension time, on the extended prototype. This
        // avoids Object.defineProperty calls for each instance created.
        if (Sub.options.props) {
          initProps$1(Sub);
        }
        if (Sub.options.computed) {
          initComputed$1(Sub);
        }
  
        // allow further extension/mixin/plugin usage
        Sub.extend = Super.extend;
        Sub.mixin = Super.mixin;
        Sub.use = Super.use;
  
        // create asset registers, so extended classes
        // can have their private assets too.
        ASSET_TYPES.forEach(function (type) {
          Sub[type] = Super[type];
        });
        // enable recursive self-lookup
        if (name) {
          Sub.options.components[name] = Sub;
        }
  
        // keep a reference to the super options at extension time.
        // later at instantiation we can check if Super's options have
        // been updated.
        Sub.superOptions = Super.options;
        Sub.extendOptions = extendOptions;
        Sub.sealedOptions = extend({}, Sub.options);
  
        // cache constructor
        cachedCtors[SuperId] = Sub;
        return Sub
      };
    }
  
    function initProps$1 (Comp) {
      var props = Comp.options.props;
      for (var key in props) {
        proxy(Comp.prototype, "_props", key);
      }
    }
  
    function initComputed$1 (Comp) {
      var computed = Comp.options.computed;
      for (var key in computed) {
        defineComputed(Comp.prototype, key, computed[key]);
      }
    }
  
    /*  */
  
    function initAssetRegisters (Vue) {
      /**
       * Create asset registration methods.
       */
      ASSET_TYPES.forEach(function (type) {
        Vue[type] = function (
          id,
          definition
        ) {
          if (!definition) {
            return this.options[type + 's'][id]
          } else {
            /* istanbul ignore if */
            if ( type === 'component') {
              validateComponentName(id);
            }
            if (type === 'component' && isPlainObject(definition)) {
              definition.name = definition.name || id;
              definition = this.options._base.extend(definition);
            }
            if (type === 'directive' && typeof definition === 'function') {
              definition = { bind: definition, update: definition };
            }
            this.options[type + 's'][id] = definition;
            return definition
          }
        };
      });
    }
  
    /*  */
  
  
  
    function getComponentName (opts) {
      return opts && (opts.Ctor.options.name || opts.tag)
    }
  
    function matches (pattern, name) {
      if (Array.isArray(pattern)) {
        return pattern.indexOf(name) > -1
      } else if (typeof pattern === 'string') {
        return pattern.split(',').indexOf(name) > -1
      } else if (isRegExp(pattern)) {
        return pattern.test(name)
      }
      /* istanbul ignore next */
      return false
    }
  
    function pruneCache (keepAliveInstance, filter) {
      var cache = keepAliveInstance.cache;
      var keys = keepAliveInstance.keys;
      var _vnode = keepAliveInstance._vnode;
      for (var key in cache) {
        var cachedNode = cache[key];
        if (cachedNode) {
          var name = getComponentName(cachedNode.componentOptions);
          if (name && !filter(name)) {
            pruneCacheEntry(cache, key, keys, _vnode);
          }
        }
      }
    }
  
    function pruneCacheEntry (
      cache,
      key,
      keys,
      current
    ) {
      var cached = cache[key];
      if (cached && (!current || cached.tag !== current.tag)) {
        cached.componentInstance.$destroy();
      }
      cache[key] = null;
      remove(keys, key);
    }
  
    var patternTypes = [String, RegExp, Array];
  
    var KeepAlive = {
      name: 'keep-alive',
      abstract: true,
  
      props: {
        include: patternTypes,
        exclude: patternTypes,
        max: [String, Number]
      },
  
      created: function created () {
        this.cache = Object.create(null);
        this.keys = [];
      },
  
      destroyed: function destroyed () {
        for (var key in this.cache) {
          pruneCacheEntry(this.cache, key, this.keys);
        }
      },
  
      mounted: function mounted () {
        var this$1 = this;
  
        this.$watch('include', function (val) {
          pruneCache(this$1, function (name) { return matches(val, name); });
        });
        this.$watch('exclude', function (val) {
          pruneCache(this$1, function (name) { return !matches(val, name); });
        });
      },
  
      render: function render () {
        var slot = this.$slots.default;
        var vnode = getFirstComponentChild(slot);
        var componentOptions = vnode && vnode.componentOptions;
        if (componentOptions) {
          // check pattern
          var name = getComponentName(componentOptions);
          var ref = this;
          var include = ref.include;
          var exclude = ref.exclude;
          if (
            // not included
            (include && (!name || !matches(include, name))) ||
            // excluded
            (exclude && name && matches(exclude, name))
          ) {
            return vnode
          }
  
          var ref$1 = this;
          var cache = ref$1.cache;
          var keys = ref$1.keys;
          var key = vnode.key == null
            // same constructor may get registered as different local components
            // so cid alone is not enough (#3269)
            ? componentOptions.Ctor.cid + (componentOptions.tag ? ("::" + (componentOptions.tag)) : '')
            : vnode.key;
          if (cache[key]) {
            vnode.componentInstance = cache[key].componentInstance;
            // make current key freshest
            remove(keys, key);
            keys.push(key);
          } else {
            cache[key] = vnode;
            keys.push(key);
            // prune oldest entry
            if (this.max && keys.length > parseInt(this.max)) {
              pruneCacheEntry(cache, keys[0], keys, this._vnode);
            }
          }
  
          vnode.data.keepAlive = true;
        }
        return vnode || (slot && slot[0])
      }
    };
  
    var builtInComponents = {
      KeepAlive: KeepAlive
    };
  
    /*  */
  
    function initGlobalAPI(Vue) {
      // config
      var configDef = {};
      configDef.get = function () { return config; };
      {
        configDef.set = function () {
          warn(
            'Do not replace the Vue.config object, set individual fields instead.'
          );
        };
      }
      Object.defineProperty(Vue, 'config', configDef);
  
      // exposed util methods.
      // NOTE: these are not considered part of the public API - avoid relying on
      // them unless you are aware of the risk.
      Vue.util = {
        warn: warn,
        extend: extend,
        mergeOptions: mergeOptions,
        defineReactive: defineReactive
      };
  
      Vue.set = set;
      Vue.delete = del;
      Vue.nextTick = nextTick;
  
      // 2.6 explicit observable API
      Vue.observable = function (obj) {
        observe(obj);
        return obj
      };
  
      Vue.options = Object.create(null);
      // 初始化 ['components', 'filters', 'directives']
      ASSET_TYPES.forEach(function (type) {
          Vue.options[type + 's'] = Object.create(null);
        });
  
      // this is used to identify the "base" constructor to extend all plain-object
      // components with in Weex's multi-instance scenarios.
      Vue.options._base = Vue;
  
      extend(Vue.options.components, builtInComponents);
  
      initUse(Vue);
      initMixin$1(Vue);
      initExtend(Vue);
      initAssetRegisters(Vue);
    }
  
    //初始化全局API
    initGlobalAPI(Vue);
  
    Object.defineProperty(Vue.prototype, '$isServer', {
      get: isServerRendering
    });
  
    Object.defineProperty(Vue.prototype, '$ssrContext', {
      get: function get() {
        /* istanbul ignore next */
        return this.$vnode && this.$vnode.ssrContext
      }
    });
  
    // expose FunctionalRenderContext for ssr runtime helper installation
    Object.defineProperty(Vue, 'FunctionalRenderContext', {
      value: FunctionalRenderContext
    });
  
    Vue.version = '2.6.11';
  
    /*  */
  
    // these are reserved for web because they are directly compiled away
    // during template compilation
    var isReservedAttr = makeMap('style,class');
  
    // attributes that should be using props for binding
    var acceptValue = makeMap('input,textarea,option,select,progress');
    var mustUseProp = function (tag, type, attr) {
      return (
        (attr === 'value' && acceptValue(tag)) && type !== 'button' ||
        (attr === 'selected' && tag === 'option') ||
        (attr === 'checked' && tag === 'input') ||
        (attr === 'muted' && tag === 'video')
      )
    };
  
    var isEnumeratedAttr = makeMap('contenteditable,draggable,spellcheck');
  
    var isValidContentEditableValue = makeMap('events,caret,typing,plaintext-only');
  
    var convertEnumeratedValue = function (key, value) {
      return isFalsyAttrValue(value) || value === 'false'
        ? 'false'
        // allow arbitrary string value for contenteditable
        : key === 'contenteditable' && isValidContentEditableValue(value)
          ? value
          : 'true'
    };
  
    var isBooleanAttr = makeMap(
      'allowfullscreen,async,autofocus,autoplay,checked,compact,controls,declare,' +
      'default,defaultchecked,defaultmuted,defaultselected,defer,disabled,' +
      'enabled,formnovalidate,hidden,indeterminate,inert,ismap,itemscope,loop,multiple,' +
      'muted,nohref,noresize,noshade,novalidate,nowrap,open,pauseonexit,readonly,' +
      'required,reversed,scoped,seamless,selected,sortable,translate,' +
      'truespeed,typemustmatch,visible'
    );
  
    var xlinkNS = 'http://www.w3.org/1999/xlink';
  
    var isXlink = function (name) {
      return name.charAt(5) === ':' && name.slice(0, 5) === 'xlink'
    };
  
    var getXlinkProp = function (name) {
      return isXlink(name) ? name.slice(6, name.length) : ''
    };
  
    var isFalsyAttrValue = function (val) {
      return val == null || val === false
    };
  
    /*  */
  
    function genClassForVnode (vnode) {
      var data = vnode.data;
      var parentNode = vnode;
      var childNode = vnode;
      while (isDef(childNode.componentInstance)) {
        childNode = childNode.componentInstance._vnode;
        if (childNode && childNode.data) {
          data = mergeClassData(childNode.data, data);
        }
      }
      while (isDef(parentNode = parentNode.parent)) {
        if (parentNode && parentNode.data) {
          data = mergeClassData(data, parentNode.data);
        }
      }
      return renderClass(data.staticClass, data.class)
    }
  
    function mergeClassData (child, parent) {
      return {
        staticClass: concat(child.staticClass, parent.staticClass),
        class: isDef(child.class)
          ? [child.class, parent.class]
          : parent.class
      }
    }
  
    function renderClass (
      staticClass,
      dynamicClass
    ) {
      if (isDef(staticClass) || isDef(dynamicClass)) {
        return concat(staticClass, stringifyClass(dynamicClass))
      }
      /* istanbul ignore next */
      return ''
    }
  
    function concat (a, b) {
      return a ? b ? (a + ' ' + b) : a : (b || '')
    }
  
    function stringifyClass (value) {
      if (Array.isArray(value)) {
        return stringifyArray(value)
      }
      if (isObject(value)) {
        return stringifyObject(value)
      }
      if (typeof value === 'string') {
        return value
      }
      /* istanbul ignore next */
      return ''
    }
  
    function stringifyArray (value) {
      var res = '';
      var stringified;
      for (var i = 0, l = value.length; i < l; i++) {
        if (isDef(stringified = stringifyClass(value[i])) && stringified !== '') {
          if (res) { res += ' '; }
          res += stringified;
        }
      }
      return res
    }
  
    function stringifyObject (value) {
      var res = '';
      for (var key in value) {
        if (value[key]) {
          if (res) { res += ' '; }
          res += key;
        }
      }
      return res
    }
  
    /*  */
  
    var namespaceMap = {
      svg: 'http://www.w3.org/2000/svg',
      math: 'http://www.w3.org/1998/Math/MathML'
    };
  
    var isHTMLTag = makeMap(
      'html,body,base,head,link,meta,style,title,' +
      'address,article,aside,footer,header,h1,h2,h3,h4,h5,h6,hgroup,nav,section,' +
      'div,dd,dl,dt,figcaption,figure,picture,hr,img,li,main,ol,p,pre,ul,' +
      'a,b,abbr,bdi,bdo,br,cite,code,data,dfn,em,i,kbd,mark,q,rp,rt,rtc,ruby,' +
      's,samp,small,span,strong,sub,sup,time,u,var,wbr,area,audio,map,track,video,' +
      'embed,object,param,source,canvas,script,noscript,del,ins,' +
      'caption,col,colgroup,table,thead,tbody,td,th,tr,' +
      'button,datalist,fieldset,form,input,label,legend,meter,optgroup,option,' +
      'output,progress,select,textarea,' +
      'details,dialog,menu,menuitem,summary,' +
      'content,element,shadow,template,blockquote,iframe,tfoot'
    );
  
    // this map is intentionally selective, only covering SVG elements that may
    // contain child elements.
    var isSVG = makeMap(
      'svg,animate,circle,clippath,cursor,defs,desc,ellipse,filter,font-face,' +
      'foreignObject,g,glyph,image,line,marker,mask,missing-glyph,path,pattern,' +
      'polygon,polyline,rect,switch,symbol,text,textpath,tspan,use,view',
      true
    );
  
    var isPreTag = function (tag) { return tag === 'pre'; };
  
    var isReservedTag = function (tag) {
      return isHTMLTag(tag) || isSVG(tag)
    };
  
    function getTagNamespace (tag) {
      if (isSVG(tag)) {
        return 'svg'
      }
      // basic support for MathML
      // note it doesn't support other MathML elements being component roots
      if (tag === 'math') {
        return 'math'
      }
    }
  
    var unknownElementCache = Object.create(null);
    function isUnknownElement (tag) {
      /* istanbul ignore if */
      if (!inBrowser) {
        return true
      }
      if (isReservedTag(tag)) {
        return false
      }
      tag = tag.toLowerCase();
      /* istanbul ignore if */
      if (unknownElementCache[tag] != null) {
        return unknownElementCache[tag]
      }
      var el = document.createElement(tag);
      if (tag.indexOf('-') > -1) {
        // http://stackoverflow.com/a/28210364/1070244
        return (unknownElementCache[tag] = (
          el.constructor === window.HTMLUnknownElement ||
          el.constructor === window.HTMLElement
        ))
      } else {
        return (unknownElementCache[tag] = /HTMLUnknownElement/.test(el.toString()))
      }
    }
  
    var isTextInputType = makeMap('text,number,password,search,email,tel,url');
  
    /*  */
  
    /**
     * Query an element selector if it's not an element already.
     */
    function query (el) {
      if (typeof el === 'string') {
        var selected = document.querySelector(el);
        if (!selected) {
           warn(
            'Cannot find element: ' + el
          );
          return document.createElement('div')
        }
        return selected
      } else {
        return el
      }
    }
  
    /*  */
  
    function createElement$1 (tagName, vnode) {
      var elm = document.createElement(tagName);
      if (tagName !== 'select') {
        return elm
      }
      // false or null will remove the attribute but undefined will not
      if (vnode.data && vnode.data.attrs && vnode.data.attrs.multiple !== undefined) {
        elm.setAttribute('multiple', 'multiple');
      }
      return elm
    }
  
    function createElementNS (namespace, tagName) {
      return document.createElementNS(namespaceMap[namespace], tagName)
    }
  
    function createTextNode (text) {
      return document.createTextNode(text)
    }
  
    function createComment (text) {
      return document.createComment(text)
    }
  
    function insertBefore (parentNode, newNode, referenceNode) {
      parentNode.insertBefore(newNode, referenceNode);
    }
  
    function removeChild (node, child) {
      node.removeChild(child);
    }
  
    function appendChild (node, child) {
      node.appendChild(child);
    }
  
    function parentNode (node) {
      return node.parentNode
    }
  
    function nextSibling (node) {
      return node.nextSibling
    }
  
    function tagName (node) {
      return node.tagName
    }
  
    function setTextContent (node, text) {
      node.textContent = text;
    }
  
    function setStyleScope (node, scopeId) {
      node.setAttribute(scopeId, '');
    }
  
    var nodeOps = /*#__PURE__*/Object.freeze({
      __proto__: null,
      createElement: createElement$1,
      createElementNS: createElementNS,
      createTextNode: createTextNode,
      createComment: createComment,
      insertBefore: insertBefore,
      removeChild: removeChild,
      appendChild: appendChild,
      parentNode: parentNode,
      nextSibling: nextSibling,
      tagName: tagName,
      setTextContent: setTextContent,
      setStyleScope: setStyleScope
    });
  
    /*  */
  
    var ref = {
      create: function create (_, vnode) {
        registerRef(vnode);
      },
      update: function update (oldVnode, vnode) {
        if (oldVnode.data.ref !== vnode.data.ref) {
          registerRef(oldVnode, true);
          registerRef(vnode);
        }
      },
      destroy: function destroy (vnode) {
        registerRef(vnode, true);
      }
    };
  
    function registerRef (vnode, isRemoval) {
      var key = vnode.data.ref;
      if (!isDef(key)) { return }
  
      var vm = vnode.context;
      var ref = vnode.componentInstance || vnode.elm;
      var refs = vm.$refs;
      if (isRemoval) {
        if (Array.isArray(refs[key])) {
          remove(refs[key], ref);
        } else if (refs[key] === ref) {
          refs[key] = undefined;
        }
      } else {
        if (vnode.data.refInFor) {
          if (!Array.isArray(refs[key])) {
            refs[key] = [ref];
          } else if (refs[key].indexOf(ref) < 0) {
            // $flow-disable-line
            refs[key].push(ref);
          }
        } else {
          refs[key] = ref;
        }
      }
    }
  
    /**
     * Virtual DOM patching algorithm based on Snabbdom by
     * Simon Friis Vindum (@paldepind)
     * Licensed under the MIT License
     * https://github.com/paldepind/snabbdom/blob/master/LICENSE
     *
     * modified by Evan You (@yyx990803)
     *
     * Not type-checking this because this file is perf-critical and the cost
     * of making flow understand it is not worth it.
     */
  
    var emptyNode = new VNode('', {}, []);
  
    var hooks = ['create', 'activate', 'update', 'remove', 'destroy'];
  
    function sameVnode (a, b) {
      return (
        a.key === b.key && (
          (
            a.tag === b.tag &&
            a.isComment === b.isComment &&
            isDef(a.data) === isDef(b.data) &&
            sameInputType(a, b)
          ) || (
            isTrue(a.isAsyncPlaceholder) &&
            a.asyncFactory === b.asyncFactory &&
            isUndef(b.asyncFactory.error)
          )
        )
      )
    }
  
    function sameInputType (a, b) {
      if (a.tag !== 'input') { return true }
      var i;
      var typeA = isDef(i = a.data) && isDef(i = i.attrs) && i.type;
      var typeB = isDef(i = b.data) && isDef(i = i.attrs) && i.type;
      return typeA === typeB || isTextInputType(typeA) && isTextInputType(typeB)
    }
  
    function createKeyToOldIdx (children, beginIdx, endIdx) {
      var i, key;
      var map = {};
      for (i = beginIdx; i <= endIdx; ++i) {
        key = children[i].key;
        if (isDef(key)) { map[key] = i; }
      }
      return map
    }
  
    function createPatchFunction (backend) {
      var i, j;
      var cbs = {};
  
      var modules = backend.modules;
      var nodeOps = backend.nodeOps;
  
      for (i = 0; i < hooks.length; ++i) {
        cbs[hooks[i]] = [];
        for (j = 0; j < modules.length; ++j) {
          if (isDef(modules[j][hooks[i]])) {
            cbs[hooks[i]].push(modules[j][hooks[i]]);
          }
        }
      }
  
      function emptyNodeAt (elm) {
        return new VNode(nodeOps.tagName(elm).toLowerCase(), {}, [], undefined, elm)
      }
  
      function createRmCb (childElm, listeners) {
        function remove () {
          if (--remove.listeners === 0) {
            removeNode(childElm);
          }
        }
        remove.listeners = listeners;
        return remove
      }
  
      function removeNode (el) {
        var parent = nodeOps.parentNode(el);
        // element may have already been removed due to v-html / v-text
        if (isDef(parent)) {
          nodeOps.removeChild(parent, el);
        }
      }
  
      function isUnknownElement (vnode, inVPre) {
        return (
          !inVPre &&
          !vnode.ns &&
          !(
            config.ignoredElements.length &&
            config.ignoredElements.some(function (ignore) {
              return isRegExp(ignore)
                ? ignore.test(vnode.tag)
                : ignore === vnode.tag
            })
          ) &&
          config.isUnknownElement(vnode.tag)
        )
      }
  
      var creatingElmInVPre = 0;
  
      function createElm (
        vnode,
        insertedVnodeQueue,
        parentElm,
        refElm,
        nested,
        ownerArray,
        index
      ) {
        if (isDef(vnode.elm) && isDef(ownerArray)) {
          // This vnode was used in a previous render!
          // now it's used as a new node, overwriting its elm would cause
          // potential patch errors down the road when it's used as an insertion
          // reference node. Instead, we clone the node on-demand before creating
          // associated DOM element for it.
          vnode = ownerArray[index] = cloneVNode(vnode);
        }
  
        vnode.isRootInsert = !nested; // for transition enter check
        if (createComponent(vnode, insertedVnodeQueue, parentElm, refElm)) {
          return
        }
  
        var data = vnode.data;
        var children = vnode.children;
        var tag = vnode.tag;
        if (isDef(tag)) {
          {
            if (data && data.pre) {
              creatingElmInVPre++;
            }
            if (isUnknownElement(vnode, creatingElmInVPre)) {
              warn(
                'Unknown custom element: <' + tag + '> - did you ' +
                'register the component correctly? For recursive components, ' +
                'make sure to provide the "name" option.',
                vnode.context
              );
            }
          }
  
          vnode.elm = vnode.ns
            ? nodeOps.createElementNS(vnode.ns, tag)
            : nodeOps.createElement(tag, vnode);
          setScope(vnode);
  
          /* istanbul ignore if */
          {
            createChildren(vnode, children, insertedVnodeQueue);
            if (isDef(data)) {
              invokeCreateHooks(vnode, insertedVnodeQueue);
            }
            insert(parentElm, vnode.elm, refElm);
          }
  
          if ( data && data.pre) {
            creatingElmInVPre--;
          }
        } else if (isTrue(vnode.isComment)) {
          vnode.elm = nodeOps.createComment(vnode.text);
          insert(parentElm, vnode.elm, refElm);
        } else {
          vnode.elm = nodeOps.createTextNode(vnode.text);
          insert(parentElm, vnode.elm, refElm);
        }
      }
  
      function createComponent (vnode, insertedVnodeQueue, parentElm, refElm) {
        var i = vnode.data;
        if (isDef(i)) {
          var isReactivated = isDef(vnode.componentInstance) && i.keepAlive;
          if (isDef(i = i.hook) && isDef(i = i.init)) {
            i(vnode, false /* hydrating */);
          }
          // after calling the init hook, if the vnode is a child component
          // it should've created a child instance and mounted it. the child
          // component also has set the placeholder vnode's elm.
          // in that case we can just return the element and be done.
          if (isDef(vnode.componentInstance)) {
            initComponent(vnode, insertedVnodeQueue);
            insert(parentElm, vnode.elm, refElm);
            if (isTrue(isReactivated)) {
              reactivateComponent(vnode, insertedVnodeQueue, parentElm, refElm);
            }
            return true
          }
        }
      }
  
      function initComponent (vnode, insertedVnodeQueue) {
        if (isDef(vnode.data.pendingInsert)) {
          insertedVnodeQueue.push.apply(insertedVnodeQueue, vnode.data.pendingInsert);
          vnode.data.pendingInsert = null;
        }
        vnode.elm = vnode.componentInstance.$el;
        if (isPatchable(vnode)) {
          invokeCreateHooks(vnode, insertedVnodeQueue);
          setScope(vnode);
        } else {
          // empty component root.
          // skip all element-related modules except for ref (#3455)
          registerRef(vnode);
          // make sure to invoke the insert hook
          insertedVnodeQueue.push(vnode);
        }
      }
  
      function reactivateComponent (vnode, insertedVnodeQueue, parentElm, refElm) {
        var i;
        // hack for #4339: a reactivated component with inner transition
        // does not trigger because the inner node's created hooks are not called
        // again. It's not ideal to involve module-specific logic in here but
        // there doesn't seem to be a better way to do it.
        var innerNode = vnode;
        while (innerNode.componentInstance) {
          innerNode = innerNode.componentInstance._vnode;
          if (isDef(i = innerNode.data) && isDef(i = i.transition)) {
            for (i = 0; i < cbs.activate.length; ++i) {
              cbs.activate[i](emptyNode, innerNode);
            }
            insertedVnodeQueue.push(innerNode);
            break
          }
        }
        // unlike a newly created component,
        // a reactivated keep-alive component doesn't insert itself
        insert(parentElm, vnode.elm, refElm);
      }
  
      function insert (parent, elm, ref) {
        if (isDef(parent)) {
          if (isDef(ref)) {
            if (nodeOps.parentNode(ref) === parent) {
              nodeOps.insertBefore(parent, elm, ref);
            }
          } else {
            nodeOps.appendChild(parent, elm);
          }
        }
      }
  
      function createChildren (vnode, children, insertedVnodeQueue) {
        if (Array.isArray(children)) {
          {
            checkDuplicateKeys(children);
          }
          for (var i = 0; i < children.length; ++i) {
            createElm(children[i], insertedVnodeQueue, vnode.elm, null, true, children, i);
          }
        } else if (isPrimitive(vnode.text)) {
          nodeOps.appendChild(vnode.elm, nodeOps.createTextNode(String(vnode.text)));
        }
      }
  
      function isPatchable (vnode) {
        while (vnode.componentInstance) {
          vnode = vnode.componentInstance._vnode;
        }
        return isDef(vnode.tag)
      }
  
      function invokeCreateHooks (vnode, insertedVnodeQueue) {
        for (var i$1 = 0; i$1 < cbs.create.length; ++i$1) {
          cbs.create[i$1](emptyNode, vnode);
        }
        i = vnode.data.hook; // Reuse variable
        if (isDef(i)) {
          if (isDef(i.create)) { i.create(emptyNode, vnode); }
          if (isDef(i.insert)) { insertedVnodeQueue.push(vnode); }
        }
      }
  
      // set scope id attribute for scoped CSS.
      // this is implemented as a special case to avoid the overhead
      // of going through the normal attribute patching process.
      function setScope (vnode) {
        var i;
        if (isDef(i = vnode.fnScopeId)) {
          nodeOps.setStyleScope(vnode.elm, i);
        } else {
          var ancestor = vnode;
          while (ancestor) {
            if (isDef(i = ancestor.context) && isDef(i = i.$options._scopeId)) {
              nodeOps.setStyleScope(vnode.elm, i);
            }
            ancestor = ancestor.parent;
          }
        }
        // for slot content they should also get the scopeId from the host instance.
        if (isDef(i = activeInstance) &&
          i !== vnode.context &&
          i !== vnode.fnContext &&
          isDef(i = i.$options._scopeId)
        ) {
          nodeOps.setStyleScope(vnode.elm, i);
        }
      }
  
      function addVnodes (parentElm, refElm, vnodes, startIdx, endIdx, insertedVnodeQueue) {
        for (; startIdx <= endIdx; ++startIdx) {
          createElm(vnodes[startIdx], insertedVnodeQueue, parentElm, refElm, false, vnodes, startIdx);
        }
      }
  
      function invokeDestroyHook (vnode) {
        var i, j;
        var data = vnode.data;
        if (isDef(data)) {
          if (isDef(i = data.hook) && isDef(i = i.destroy)) { i(vnode); }
          for (i = 0; i < cbs.destroy.length; ++i) { cbs.destroy[i](vnode); }
        }
        if (isDef(i = vnode.children)) {
          for (j = 0; j < vnode.children.length; ++j) {
            invokeDestroyHook(vnode.children[j]);
          }
        }
      }
  
      function removeVnodes (vnodes, startIdx, endIdx) {
        for (; startIdx <= endIdx; ++startIdx) {
          var ch = vnodes[startIdx];
          if (isDef(ch)) {
            if (isDef(ch.tag)) {
              removeAndInvokeRemoveHook(ch);
              invokeDestroyHook(ch);
            } else { // Text node
              removeNode(ch.elm);
            }
          }
        }
      }
  
      function removeAndInvokeRemoveHook (vnode, rm) {
        if (isDef(rm) || isDef(vnode.data)) {
          var i;
          var listeners = cbs.remove.length + 1;
          if (isDef(rm)) {
            // we have a recursively passed down rm callback
            // increase the listeners count
            rm.listeners += listeners;
          } else {
            // directly removing
            rm = createRmCb(vnode.elm, listeners);
          }
          // recursively invoke hooks on child component root node
          if (isDef(i = vnode.componentInstance) && isDef(i = i._vnode) && isDef(i.data)) {
            removeAndInvokeRemoveHook(i, rm);
          }
          for (i = 0; i < cbs.remove.length; ++i) {
            cbs.remove[i](vnode, rm);
          }
          if (isDef(i = vnode.data.hook) && isDef(i = i.remove)) {
            i(vnode, rm);
          } else {
            rm();
          }
        } else {
          removeNode(vnode.elm);
        }
      }
  
      function updateChildren (parentElm, oldCh, newCh, insertedVnodeQueue, removeOnly) {
        var oldStartIdx = 0;
        var newStartIdx = 0;
        var oldEndIdx = oldCh.length - 1;
        var oldStartVnode = oldCh[0];
        var oldEndVnode = oldCh[oldEndIdx];
        var newEndIdx = newCh.length - 1;
        var newStartVnode = newCh[0];
        var newEndVnode = newCh[newEndIdx];
        var oldKeyToIdx, idxInOld, vnodeToMove, refElm;
  
        // removeOnly is a special flag used only by <transition-group>
        // to ensure removed elements stay in correct relative positions
        // during leaving transitions
        var canMove = !removeOnly;
  
        {
          checkDuplicateKeys(newCh);
        }
  
        while (oldStartIdx <= oldEndIdx && newStartIdx <= newEndIdx) {
          if (isUndef(oldStartVnode)) {
            oldStartVnode = oldCh[++oldStartIdx]; // Vnode has been moved left
          } else if (isUndef(oldEndVnode)) {
            oldEndVnode = oldCh[--oldEndIdx];
          } else if (sameVnode(oldStartVnode, newStartVnode)) {
            patchVnode(oldStartVnode, newStartVnode, insertedVnodeQueue, newCh, newStartIdx);
            oldStartVnode = oldCh[++oldStartIdx];
            newStartVnode = newCh[++newStartIdx];
          } else if (sameVnode(oldEndVnode, newEndVnode)) {
            patchVnode(oldEndVnode, newEndVnode, insertedVnodeQueue, newCh, newEndIdx);
            oldEndVnode = oldCh[--oldEndIdx];
            newEndVnode = newCh[--newEndIdx];
          } else if (sameVnode(oldStartVnode, newEndVnode)) { // Vnode moved right
            patchVnode(oldStartVnode, newEndVnode, insertedVnodeQueue, newCh, newEndIdx);
            canMove && nodeOps.insertBefore(parentElm, oldStartVnode.elm, nodeOps.nextSibling(oldEndVnode.elm));
            oldStartVnode = oldCh[++oldStartIdx];
            newEndVnode = newCh[--newEndIdx];
          } else if (sameVnode(oldEndVnode, newStartVnode)) { // Vnode moved left
            patchVnode(oldEndVnode, newStartVnode, insertedVnodeQueue, newCh, newStartIdx);
            canMove && nodeOps.insertBefore(parentElm, oldEndVnode.elm, oldStartVnode.elm);
            oldEndVnode = oldCh[--oldEndIdx];
            newStartVnode = newCh[++newStartIdx];
          } else {
            if (isUndef(oldKeyToIdx)) { oldKeyToIdx = createKeyToOldIdx(oldCh, oldStartIdx, oldEndIdx); }
            idxInOld = isDef(newStartVnode.key)
              ? oldKeyToIdx[newStartVnode.key]
              : findIdxInOld(newStartVnode, oldCh, oldStartIdx, oldEndIdx);
            if (isUndef(idxInOld)) { // New element
              createElm(newStartVnode, insertedVnodeQueue, parentElm, oldStartVnode.elm, false, newCh, newStartIdx);
            } else {
              vnodeToMove = oldCh[idxInOld];
              if (sameVnode(vnodeToMove, newStartVnode)) {
                patchVnode(vnodeToMove, newStartVnode, insertedVnodeQueue, newCh, newStartIdx);
                oldCh[idxInOld] = undefined;
                canMove && nodeOps.insertBefore(parentElm, vnodeToMove.elm, oldStartVnode.elm);
              } else {
                // same key but different element. treat as new element
                createElm(newStartVnode, insertedVnodeQueue, parentElm, oldStartVnode.elm, false, newCh, newStartIdx);
              }
            }
            newStartVnode = newCh[++newStartIdx];
          }
        }
        if (oldStartIdx > oldEndIdx) {
          refElm = isUndef(newCh[newEndIdx + 1]) ? null : newCh[newEndIdx + 1].elm;
          addVnodes(parentElm, refElm, newCh, newStartIdx, newEndIdx, insertedVnodeQueue);
        } else if (newStartIdx > newEndIdx) {
          removeVnodes(oldCh, oldStartIdx, oldEndIdx);
        }
      }
  
      function checkDuplicateKeys (children) {
        var seenKeys = {};
        for (var i = 0; i < children.length; i++) {
          var vnode = children[i];
          var key = vnode.key;
          if (isDef(key)) {
            if (seenKeys[key]) {
              warn(
                ("Duplicate keys detected: '" + key + "'. This may cause an update error."),
                vnode.context
              );
            } else {
              seenKeys[key] = true;
            }
          }
        }
      }
  
      function findIdxInOld (node, oldCh, start, end) {
        for (var i = start; i < end; i++) {
          var c = oldCh[i];
          if (isDef(c) && sameVnode(node, c)) { return i }
        }
      }
  
      function patchVnode (
        oldVnode,
        vnode,
        insertedVnodeQueue,
        ownerArray,
        index,
        removeOnly
      ) {
        if (oldVnode === vnode) {
          return
        }
  
        if (isDef(vnode.elm) && isDef(ownerArray)) {
          // clone reused vnode
          vnode = ownerArray[index] = cloneVNode(vnode);
        }
  
        var elm = vnode.elm = oldVnode.elm;
  
        if (isTrue(oldVnode.isAsyncPlaceholder)) {
          if (isDef(vnode.asyncFactory.resolved)) {
            hydrate(oldVnode.elm, vnode, insertedVnodeQueue);
          } else {
            vnode.isAsyncPlaceholder = true;
          }
          return
        }
  
        // reuse element for static trees.
        // note we only do this if the vnode is cloned -
        // if the new node is not cloned it means the render functions have been
        // reset by the hot-reload-api and we need to do a proper re-render.
        if (isTrue(vnode.isStatic) &&
          isTrue(oldVnode.isStatic) &&
          vnode.key === oldVnode.key &&
          (isTrue(vnode.isCloned) || isTrue(vnode.isOnce))
        ) {
          vnode.componentInstance = oldVnode.componentInstance;
          return
        }
  
        var i;
        var data = vnode.data;
        if (isDef(data) && isDef(i = data.hook) && isDef(i = i.prepatch)) {
          i(oldVnode, vnode);
        }
  
        var oldCh = oldVnode.children;
        var ch = vnode.children;
        if (isDef(data) && isPatchable(vnode)) {
          for (i = 0; i < cbs.update.length; ++i) { cbs.update[i](oldVnode, vnode); }
          if (isDef(i = data.hook) && isDef(i = i.update)) { i(oldVnode, vnode); }
        }
        if (isUndef(vnode.text)) {
          if (isDef(oldCh) && isDef(ch)) {
            if (oldCh !== ch) { updateChildren(elm, oldCh, ch, insertedVnodeQueue, removeOnly); }
          } else if (isDef(ch)) {
            {
              checkDuplicateKeys(ch);
            }
            if (isDef(oldVnode.text)) { nodeOps.setTextContent(elm, ''); }
            addVnodes(elm, null, ch, 0, ch.length - 1, insertedVnodeQueue);
          } else if (isDef(oldCh)) {
            removeVnodes(oldCh, 0, oldCh.length - 1);
          } else if (isDef(oldVnode.text)) {
            nodeOps.setTextContent(elm, '');
          }
        } else if (oldVnode.text !== vnode.text) {
          nodeOps.setTextContent(elm, vnode.text);
        }
        if (isDef(data)) {
          if (isDef(i = data.hook) && isDef(i = i.postpatch)) { i(oldVnode, vnode); }
        }
      }
  
      function invokeInsertHook (vnode, queue, initial) {
        // delay insert hooks for component root nodes, invoke them after the
        // element is really inserted
        if (isTrue(initial) && isDef(vnode.parent)) {
          vnode.parent.data.pendingInsert = queue;
        } else {
          for (var i = 0; i < queue.length; ++i) {
            queue[i].data.hook.insert(queue[i]);
          }
        }
      }
  
      var hydrationBailed = false;
      // list of modules that can skip create hook during hydration because they
      // are already rendered on the client or has no need for initialization
      // Note: style is excluded because it relies on initial clone for future
      // deep updates (#7063).
      var isRenderedModule = makeMap('attrs,class,staticClass,staticStyle,key');
  
      // Note: this is a browser-only function so we can assume elms are DOM nodes.
      function hydrate (elm, vnode, insertedVnodeQueue, inVPre) {
        var i;
        var tag = vnode.tag;
        var data = vnode.data;
        var children = vnode.children;
        inVPre = inVPre || (data && data.pre);
        vnode.elm = elm;
  
        if (isTrue(vnode.isComment) && isDef(vnode.asyncFactory)) {
          vnode.isAsyncPlaceholder = true;
          return true
        }
        // assert node match
        {
          if (!assertNodeMatch(elm, vnode, inVPre)) {
            return false
          }
        }
        if (isDef(data)) {
          if (isDef(i = data.hook) && isDef(i = i.init)) { i(vnode, true /* hydrating */); }
          if (isDef(i = vnode.componentInstance)) {
            // child component. it should have hydrated its own tree.
            initComponent(vnode, insertedVnodeQueue);
            return true
          }
        }
        if (isDef(tag)) {
          if (isDef(children)) {
            // empty element, allow client to pick up and populate children
            if (!elm.hasChildNodes()) {
              createChildren(vnode, children, insertedVnodeQueue);
            } else {
              // v-html and domProps: innerHTML
              if (isDef(i = data) && isDef(i = i.domProps) && isDef(i = i.innerHTML)) {
                if (i !== elm.innerHTML) {
                  /* istanbul ignore if */
                  if (
                    typeof console !== 'undefined' &&
                    !hydrationBailed
                  ) {
                    hydrationBailed = true;
                    console.warn('Parent: ', elm);
                    console.warn('server innerHTML: ', i);
                    console.warn('client innerHTML: ', elm.innerHTML);
                  }
                  return false
                }
              } else {
                // iterate and compare children lists
                var childrenMatch = true;
                var childNode = elm.firstChild;
                for (var i$1 = 0; i$1 < children.length; i$1++) {
                  if (!childNode || !hydrate(childNode, children[i$1], insertedVnodeQueue, inVPre)) {
                    childrenMatch = false;
                    break
                  }
                  childNode = childNode.nextSibling;
                }
                // if childNode is not null, it means the actual childNodes list is
                // longer than the virtual children list.
                if (!childrenMatch || childNode) {
                  /* istanbul ignore if */
                  if (
                    typeof console !== 'undefined' &&
                    !hydrationBailed
                  ) {
                    hydrationBailed = true;
                    console.warn('Parent: ', elm);
                    console.warn('Mismatching childNodes vs. VNodes: ', elm.childNodes, children);
                  }
                  return false
                }
              }
            }
          }
          if (isDef(data)) {
            var fullInvoke = false;
            for (var key in data) {
              if (!isRenderedModule(key)) {
                fullInvoke = true;
                invokeCreateHooks(vnode, insertedVnodeQueue);
                break
              }
            }
            if (!fullInvoke && data['class']) {
              // ensure collecting deps for deep class bindings for future updates
              traverse(data['class']);
            }
          }
        } else if (elm.data !== vnode.text) {
          elm.data = vnode.text;
        }
        return true
      }
  
      function assertNodeMatch (node, vnode, inVPre) {
        if (isDef(vnode.tag)) {
          return vnode.tag.indexOf('vue-component') === 0 || (
            !isUnknownElement(vnode, inVPre) &&
            vnode.tag.toLowerCase() === (node.tagName && node.tagName.toLowerCase())
          )
        } else {
          return node.nodeType === (vnode.isComment ? 8 : 3)
        }
      }
  
      return function patch (oldVnode, vnode, hydrating, removeOnly) {
        if (isUndef(vnode)) {
          if (isDef(oldVnode)) { invokeDestroyHook(oldVnode); }
          return
        }
  
        var isInitialPatch = false;
        var insertedVnodeQueue = [];
  
        if (isUndef(oldVnode)) {
          // empty mount (likely as component), create new root element
          isInitialPatch = true;
          createElm(vnode, insertedVnodeQueue);
        } else {
          var isRealElement = isDef(oldVnode.nodeType);
          if (!isRealElement && sameVnode(oldVnode, vnode)) {
            // patch existing root node
            patchVnode(oldVnode, vnode, insertedVnodeQueue, null, null, removeOnly);
          } else {
            if (isRealElement) {
              // mounting to a real element
              // check if this is server-rendered content and if we can perform
              // a successful hydration.
              if (oldVnode.nodeType === 1 && oldVnode.hasAttribute(SSR_ATTR)) {
                oldVnode.removeAttribute(SSR_ATTR);
                hydrating = true;
              }
              if (isTrue(hydrating)) {
                if (hydrate(oldVnode, vnode, insertedVnodeQueue)) {
                  invokeInsertHook(vnode, insertedVnodeQueue, true);
                  return oldVnode
                } else {
                  warn(
                    'The client-side rendered virtual DOM tree is not matching ' +
                    'server-rendered content. This is likely caused by incorrect ' +
                    'HTML markup, for example nesting block-level elements inside ' +
                    '<p>, or missing <tbody>. Bailing hydration and performing ' +
                    'full client-side render.'
                  );
                }
              }
              // either not server-rendered, or hydration failed.
              // create an empty node and replace it
              oldVnode = emptyNodeAt(oldVnode);
            }
  
            // replacing existing element
            var oldElm = oldVnode.elm;
            var parentElm = nodeOps.parentNode(oldElm);
  
            // create new node
            createElm(
              vnode,
              insertedVnodeQueue,
              // extremely rare edge case: do not insert if old element is in a
              // leaving transition. Only happens when combining transition +
              // keep-alive + HOCs. (#4590)
              oldElm._leaveCb ? null : parentElm,
              nodeOps.nextSibling(oldElm)
            );
  
            // update parent placeholder node element, recursively
            if (isDef(vnode.parent)) {
              var ancestor = vnode.parent;
              var patchable = isPatchable(vnode);
              while (ancestor) {
                for (var i = 0; i < cbs.destroy.length; ++i) {
                  cbs.destroy[i](ancestor);
                }
                ancestor.elm = vnode.elm;
                if (patchable) {
                  for (var i$1 = 0; i$1 < cbs.create.length; ++i$1) {
                    cbs.create[i$1](emptyNode, ancestor);
                  }
                  // #6513
                  // invoke insert hooks that may have been merged by create hooks.
                  // e.g. for directives that uses the "inserted" hook.
                  var insert = ancestor.data.hook.insert;
                  if (insert.merged) {
                    // start at index 1 to avoid re-invoking component mounted hook
                    for (var i$2 = 1; i$2 < insert.fns.length; i$2++) {
                      insert.fns[i$2]();
                    }
                  }
                } else {
                  registerRef(ancestor);
                }
                ancestor = ancestor.parent;
              }
            }
  
            // destroy old node
            if (isDef(parentElm)) {
              removeVnodes([oldVnode], 0, 0);
            } else if (isDef(oldVnode.tag)) {
              invokeDestroyHook(oldVnode);
            }
          }
        }
  
        invokeInsertHook(vnode, insertedVnodeQueue, isInitialPatch);
        return vnode.elm
      }
    }
  
    /*  */
  
    var directives = {
      create: updateDirectives,
      update: updateDirectives,
      destroy: function unbindDirectives (vnode) {
        updateDirectives(vnode, emptyNode);
      }
    };
  
    function updateDirectives (oldVnode, vnode) {
      if (oldVnode.data.directives || vnode.data.directives) {
        _update(oldVnode, vnode);
      }
    }
  
    function _update (oldVnode, vnode) {
      var isCreate = oldVnode === emptyNode;
      var isDestroy = vnode === emptyNode;
      var oldDirs = normalizeDirectives$1(oldVnode.data.directives, oldVnode.context);
      var newDirs = normalizeDirectives$1(vnode.data.directives, vnode.context);
  
      var dirsWithInsert = [];
      var dirsWithPostpatch = [];
  
      var key, oldDir, dir;
      for (key in newDirs) {
        oldDir = oldDirs[key];
        dir = newDirs[key];
        if (!oldDir) {
          // new directive, bind
          callHook$1(dir, 'bind', vnode, oldVnode);
          if (dir.def && dir.def.inserted) {
            dirsWithInsert.push(dir);
          }
        } else {
          // existing directive, update
          dir.oldValue = oldDir.value;
          dir.oldArg = oldDir.arg;
          callHook$1(dir, 'update', vnode, oldVnode);
          if (dir.def && dir.def.componentUpdated) {
            dirsWithPostpatch.push(dir);
          }
        }
      }
  
      if (dirsWithInsert.length) {
        var callInsert = function () {
          for (var i = 0; i < dirsWithInsert.length; i++) {
            callHook$1(dirsWithInsert[i], 'inserted', vnode, oldVnode);
          }
        };
        if (isCreate) {
          mergeVNodeHook(vnode, 'insert', callInsert);
        } else {
          callInsert();
        }
      }
  
      if (dirsWithPostpatch.length) {
        mergeVNodeHook(vnode, 'postpatch', function () {
          for (var i = 0; i < dirsWithPostpatch.length; i++) {
            callHook$1(dirsWithPostpatch[i], 'componentUpdated', vnode, oldVnode);
          }
        });
      }
  
      if (!isCreate) {
        for (key in oldDirs) {
          if (!newDirs[key]) {
            // no longer present, unbind
            callHook$1(oldDirs[key], 'unbind', oldVnode, oldVnode, isDestroy);
          }
        }
      }
    }
  
    var emptyModifiers = Object.create(null);
  
    function normalizeDirectives$1 (
      dirs,
      vm
    ) {
      var res = Object.create(null);
      if (!dirs) {
        // $flow-disable-line
        return res
      }
      var i, dir;
      for (i = 0; i < dirs.length; i++) {
        dir = dirs[i];
        if (!dir.modifiers) {
          // $flow-disable-line
          dir.modifiers = emptyModifiers;
        }
        res[getRawDirName(dir)] = dir;
        dir.def = resolveAsset(vm.$options, 'directives', dir.name, true);
      }
      // $flow-disable-line
      return res
    }
  
    function getRawDirName (dir) {
      return dir.rawName || ((dir.name) + "." + (Object.keys(dir.modifiers || {}).join('.')))
    }
  
    function callHook$1 (dir, hook, vnode, oldVnode, isDestroy) {
      var fn = dir.def && dir.def[hook];
      if (fn) {
        try {
          fn(vnode.elm, dir, vnode, oldVnode, isDestroy);
        } catch (e) {
          handleError(e, vnode.context, ("directive " + (dir.name) + " " + hook + " hook"));
        }
      }
    }
  
    var baseModules = [
      ref,
      directives
    ];
  
    /*  */
  
    function updateAttrs (oldVnode, vnode) {
      var opts = vnode.componentOptions;
      if (isDef(opts) && opts.Ctor.options.inheritAttrs === false) {
        return
      }
      if (isUndef(oldVnode.data.attrs) && isUndef(vnode.data.attrs)) {
        return
      }
      var key, cur, old;
      var elm = vnode.elm;
      var oldAttrs = oldVnode.data.attrs || {};
      var attrs = vnode.data.attrs || {};
      // clone observed objects, as the user probably wants to mutate it
      if (isDef(attrs.__ob__)) {
        attrs = vnode.data.attrs = extend({}, attrs);
      }
  
      for (key in attrs) {
        cur = attrs[key];
        old = oldAttrs[key];
        if (old !== cur) {
          setAttr(elm, key, cur);
        }
      }
      // #4391: in IE9, setting type can reset value for input[type=radio]
      // #6666: IE/Edge forces progress value down to 1 before setting a max
      /* istanbul ignore if */
      if ((isIE || isEdge) && attrs.value !== oldAttrs.value) {
        setAttr(elm, 'value', attrs.value);
      }
      for (key in oldAttrs) {
        if (isUndef(attrs[key])) {
          if (isXlink(key)) {
            elm.removeAttributeNS(xlinkNS, getXlinkProp(key));
          } else if (!isEnumeratedAttr(key)) {
            elm.removeAttribute(key);
          }
        }
      }
    }
  
    function setAttr (el, key, value) {
      if (el.tagName.indexOf('-') > -1) {
        baseSetAttr(el, key, value);
      } else if (isBooleanAttr(key)) {
        // set attribute for blank value
        // e.g. <option disabled>Select one</option>
        if (isFalsyAttrValue(value)) {
          el.removeAttribute(key);
        } else {
          // technically allowfullscreen is a boolean attribute for <iframe>,
          // but Flash expects a value of "true" when used on <embed> tag
          value = key === 'allowfullscreen' && el.tagName === 'EMBED'
            ? 'true'
            : key;
          el.setAttribute(key, value);
        }
      } else if (isEnumeratedAttr(key)) {
        el.setAttribute(key, convertEnumeratedValue(key, value));
      } else if (isXlink(key)) {
        if (isFalsyAttrValue(value)) {
          el.removeAttributeNS(xlinkNS, getXlinkProp(key));
        } else {
          el.setAttributeNS(xlinkNS, key, value);
        }
      } else {
        baseSetAttr(el, key, value);
      }
    }
  
    function baseSetAttr (el, key, value) {
      if (isFalsyAttrValue(value)) {
        el.removeAttribute(key);
      } else {
        // #7138: IE10 & 11 fires input event when setting placeholder on
        // <textarea>... block the first input event and remove the blocker
        // immediately.
        /* istanbul ignore if */
        if (
          isIE && !isIE9 &&
          el.tagName === 'TEXTAREA' &&
          key === 'placeholder' && value !== '' && !el.__ieph
        ) {
          var blocker = function (e) {
            e.stopImmediatePropagation();
            el.removeEventListener('input', blocker);
          };
          el.addEventListener('input', blocker);
          // $flow-disable-line
          el.__ieph = true; /* IE placeholder patched */
        }
        el.setAttribute(key, value);
      }
    }
  
    var attrs = {
      create: updateAttrs,
      update: updateAttrs
    };
  
    /*  */
  
    function updateClass (oldVnode, vnode) {
      var el = vnode.elm;
      var data = vnode.data;
      var oldData = oldVnode.data;
      if (
        isUndef(data.staticClass) &&
        isUndef(data.class) && (
          isUndef(oldData) || (
            isUndef(oldData.staticClass) &&
            isUndef(oldData.class)
          )
        )
      ) {
        return
      }
  
      var cls = genClassForVnode(vnode);
  
      // handle transition classes
      var transitionClass = el._transitionClasses;
      if (isDef(transitionClass)) {
        cls = concat(cls, stringifyClass(transitionClass));
      }
  
      // set the class
      if (cls !== el._prevClass) {
        el.setAttribute('class', cls);
        el._prevClass = cls;
      }
    }
  
    var klass = {
      create: updateClass,
      update: updateClass
    };
  
    /*  */
  
    var validDivisionCharRE = /[\w).+\-_$\]]/;
  
    function parseFilters (exp) {
      var inSingle = false;
      var inDouble = false;
      var inTemplateString = false;
      var inRegex = false;
      var curly = 0;
      var square = 0;
      var paren = 0;
      var lastFilterIndex = 0;
      var c, prev, i, expression, filters;
  
      for (i = 0; i < exp.length; i++) {
        prev = c;
        c = exp.charCodeAt(i);
        if (inSingle) {
          if (c === 0x27 && prev !== 0x5C) { inSingle = false; }
        } else if (inDouble) {
          if (c === 0x22 && prev !== 0x5C) { inDouble = false; }
        } else if (inTemplateString) {
          if (c === 0x60 && prev !== 0x5C) { inTemplateString = false; }
        } else if (inRegex) {
          if (c === 0x2f && prev !== 0x5C) { inRegex = false; }
        } else if (
          c === 0x7C && // pipe
          exp.charCodeAt(i + 1) !== 0x7C &&
          exp.charCodeAt(i - 1) !== 0x7C &&
          !curly && !square && !paren
        ) {
          if (expression === undefined) {
            // first filter, end of expression
            lastFilterIndex = i + 1;
            expression = exp.slice(0, i).trim();
          } else {
            pushFilter();
          }
        } else {
          switch (c) {
            case 0x22: inDouble = true; break         // "
            case 0x27: inSingle = true; break         // '
            case 0x60: inTemplateString = true; break // `
            case 0x28: paren++; break                 // (
            case 0x29: paren--; break                 // )
            case 0x5B: square++; break                // [
            case 0x5D: square--; break                // ]
            case 0x7B: curly++; break                 // {
            case 0x7D: curly--; break                 // }
          }
          if (c === 0x2f) { // /
            var j = i - 1;
            var p = (void 0);
            // find first non-whitespace prev char
            for (; j >= 0; j--) {
              p = exp.charAt(j);
              if (p !== ' ') { break }
            }
            if (!p || !validDivisionCharRE.test(p)) {
              inRegex = true;
            }
          }
        }
      }
  
      if (expression === undefined) {
        expression = exp.slice(0, i).trim();
      } else if (lastFilterIndex !== 0) {
        pushFilter();
      }
  
      function pushFilter () {
        (filters || (filters = [])).push(exp.slice(lastFilterIndex, i).trim());
        lastFilterIndex = i + 1;
      }
  
      if (filters) {
        for (i = 0; i < filters.length; i++) {
          expression = wrapFilter(expression, filters[i]);
        }
      }
  
      return expression
    }
  
    function wrapFilter (exp, filter) {
      var i = filter.indexOf('(');
      if (i < 0) {
        // _f: resolveFilter
        return ("_f(\"" + filter + "\")(" + exp + ")")
      } else {
        var name = filter.slice(0, i);
        var args = filter.slice(i + 1);
        return ("_f(\"" + name + "\")(" + exp + (args !== ')' ? ',' + args : args))
      }
    }
  
    /*  */
  
  
  
    /* eslint-disable no-unused-vars */
    function baseWarn (msg, range) {
      console.error(("[Vue compiler]: " + msg));
    }
    /* eslint-enable no-unused-vars */
  
    function pluckModuleFunction (
      modules,
      key
    ) {
      return modules
        ? modules.map(function (m) { return m[key]; }).filter(function (_) { return _; })
        : []
    }
  
    function addProp (el, name, value, range, dynamic) {
      (el.props || (el.props = [])).push(rangeSetItem({ name: name, value: value, dynamic: dynamic }, range));
      el.plain = false;
    }
  
    function addAttr (el, name, value, range, dynamic) {
      var attrs = dynamic
        ? (el.dynamicAttrs || (el.dynamicAttrs = []))
        : (el.attrs || (el.attrs = []));
      attrs.push(rangeSetItem({ name: name, value: value, dynamic: dynamic }, range));
      el.plain = false;
    }
  
    // add a raw attr (use this in preTransforms)
    function addRawAttr (el, name, value, range) {
      el.attrsMap[name] = value;
      el.attrsList.push(rangeSetItem({ name: name, value: value }, range));
    }
  
    function addDirective (
      el,
      name,
      rawName,
      value,
      arg,
      isDynamicArg,
      modifiers,
      range
    ) {
      (el.directives || (el.directives = [])).push(rangeSetItem({
        name: name,
        rawName: rawName,
        value: value,
        arg: arg,
        isDynamicArg: isDynamicArg,
        modifiers: modifiers
      }, range));
      el.plain = false;
    }
  
    function prependModifierMarker (symbol, name, dynamic) {
      return dynamic
        ? ("_p(" + name + ",\"" + symbol + "\")")
        : symbol + name // mark the event as captured
    }
  
    function addHandler (
      el,
      name,
      value,
      modifiers,
      important,
      warn,
      range,
      dynamic
    ) {
      modifiers = modifiers || emptyObject;
      // warn prevent and passive modifier
      /* istanbul ignore if */
      if (
         warn &&
        modifiers.prevent && modifiers.passive
      ) {
        warn(
          'passive and prevent can\'t be used together. ' +
          'Passive handler can\'t prevent default event.',
          range
        );
      }
  
      // normalize click.right and click.middle since they don't actually fire
      // this is technically browser-specific, but at least for now browsers are
      // the only target envs that have right/middle clicks.
      if (modifiers.right) {
        if (dynamic) {
          name = "(" + name + ")==='click'?'contextmenu':(" + name + ")";
        } else if (name === 'click') {
          name = 'contextmenu';
          delete modifiers.right;
        }
      } else if (modifiers.middle) {
        if (dynamic) {
          name = "(" + name + ")==='click'?'mouseup':(" + name + ")";
        } else if (name === 'click') {
          name = 'mouseup';
        }
      }
  
      // check capture modifier
      if (modifiers.capture) {
        delete modifiers.capture;
        name = prependModifierMarker('!', name, dynamic);
      }
      if (modifiers.once) {
        delete modifiers.once;
        name = prependModifierMarker('~', name, dynamic);
      }
      /* istanbul ignore if */
      if (modifiers.passive) {
        delete modifiers.passive;
        name = prependModifierMarker('&', name, dynamic);
      }
  
      var events;
      if (modifiers.native) {
        delete modifiers.native;
        events = el.nativeEvents || (el.nativeEvents = {});
      } else {
        events = el.events || (el.events = {});
      }
  
      var newHandler = rangeSetItem({ value: value.trim(), dynamic: dynamic }, range);
      if (modifiers !== emptyObject) {
        newHandler.modifiers = modifiers;
      }
  
      var handlers = events[name];
      /* istanbul ignore if */
      if (Array.isArray(handlers)) {
        important ? handlers.unshift(newHandler) : handlers.push(newHandler);
      } else if (handlers) {
        events[name] = important ? [newHandler, handlers] : [handlers, newHandler];
      } else {
        events[name] = newHandler;
      }
  
      el.plain = false;
    }
  
    function getRawBindingAttr (
      el,
      name
    ) {
      return el.rawAttrsMap[':' + name] ||
        el.rawAttrsMap['v-bind:' + name] ||
        el.rawAttrsMap[name]
    }
  
    function getBindingAttr (
      el,
      name,
      getStatic
    ) {
      var dynamicValue =
        getAndRemoveAttr(el, ':' + name) ||
        getAndRemoveAttr(el, 'v-bind:' + name);
      if (dynamicValue != null) {
        return parseFilters(dynamicValue)
      } else if (getStatic !== false) {
        var staticValue = getAndRemoveAttr(el, name);
        if (staticValue != null) {
          return JSON.stringify(staticValue)
        }
      }
    }
  
    // note: this only removes the attr from the Array (attrsList) so that it
    // doesn't get processed by processAttrs.
    // By default it does NOT remove it from the map (attrsMap) because the map is
    // needed during codegen.
    function getAndRemoveAttr (
      el,
      name,
      removeFromMap
    ) {
      var val;
      if ((val = el.attrsMap[name]) != null) {
        var list = el.attrsList;
        for (var i = 0, l = list.length; i < l; i++) {
          if (list[i].name === name) {
            list.splice(i, 1);
            break
          }
        }
      }
      if (removeFromMap) {
        delete el.attrsMap[name];
      }
      return val
    }
  
    function getAndRemoveAttrByRegex (
      el,
      name
    ) {
      var list = el.attrsList;
      for (var i = 0, l = list.length; i < l; i++) {
        var attr = list[i];
        if (name.test(attr.name)) {
          list.splice(i, 1);
          return attr
        }
      }
    }
  
    function rangeSetItem (
      item,
      range
    ) {
      if (range) {
        if (range.start != null) {
          item.start = range.start;
        }
        if (range.end != null) {
          item.end = range.end;
        }
      }
      return item
    }
  
    /*  */
  
    /**
     * Cross-platform code generation for component v-model
     */
    function genComponentModel (
      el,
      value,
      modifiers
    ) {
      var ref = modifiers || {};
      var number = ref.number;
      var trim = ref.trim;
  
      var baseValueExpression = '$$v';
      var valueExpression = baseValueExpression;
      if (trim) {
        valueExpression =
          "(typeof " + baseValueExpression + " === 'string'" +
          "? " + baseValueExpression + ".trim()" +
          ": " + baseValueExpression + ")";
      }
      if (number) {
        valueExpression = "_n(" + valueExpression + ")";
      }
      var assignment = genAssignmentCode(value, valueExpression);
  
      el.model = {
        value: ("(" + value + ")"),
        expression: JSON.stringify(value),
        callback: ("function (" + baseValueExpression + ") {" + assignment + "}")
      };
    }
  
    /**
     * Cross-platform codegen helper for generating v-model value assignment code.
     */
    function genAssignmentCode (
      value,
      assignment
    ) {
      var res = parseModel(value);
      if (res.key === null) {
        return (value + "=" + assignment)
      } else {
        return ("$set(" + (res.exp) + ", " + (res.key) + ", " + assignment + ")")
      }
    }
  
    /**
     * Parse a v-model expression into a base path and a final key segment.
     * Handles both dot-path and possible square brackets.
     *
     * Possible cases:
     *
     * - test
     * - test[key]
     * - test[test1[key]]
     * - test["a"][key]
     * - xxx.test[a[a].test1[key]]
     * - test.xxx.a["asa"][test1[key]]
     *
     */
  
    var len, str, chr, index$1, expressionPos, expressionEndPos;
  
  
  
    function parseModel (val) {
      // Fix https://github.com/vuejs/vue/pull/7730
      // allow v-model="obj.val " (trailing whitespace)
      val = val.trim();
      len = val.length;
  
      if (val.indexOf('[') < 0 || val.lastIndexOf(']') < len - 1) {
        index$1 = val.lastIndexOf('.');
        if (index$1 > -1) {
          return {
            exp: val.slice(0, index$1),
            key: '"' + val.slice(index$1 + 1) + '"'
          }
        } else {
          return {
            exp: val,
            key: null
          }
        }
      }
  
      str = val;
      index$1 = expressionPos = expressionEndPos = 0;
  
      while (!eof()) {
        chr = next();
        /* istanbul ignore if */
        if (isStringStart(chr)) {
          parseString(chr);
        } else if (chr === 0x5B) {
          parseBracket(chr);
        }
      }
  
      return {
        exp: val.slice(0, expressionPos),
        key: val.slice(expressionPos + 1, expressionEndPos)
      }
    }
  
    function next () {
      return str.charCodeAt(++index$1)
    }
  
    function eof () {
      return index$1 >= len
    }
  
    function isStringStart (chr) {
      return chr === 0x22 || chr === 0x27
    }
  
    function parseBracket (chr) {
      var inBracket = 1;
      expressionPos = index$1;
      while (!eof()) {
        chr = next();
        if (isStringStart(chr)) {
          parseString(chr);
          continue
        }
        if (chr === 0x5B) { inBracket++; }
        if (chr === 0x5D) { inBracket--; }
        if (inBracket === 0) {
          expressionEndPos = index$1;
          break
        }
      }
    }
  
    function parseString (chr) {
      var stringQuote = chr;
      while (!eof()) {
        chr = next();
        if (chr === stringQuote) {
          break
        }
      }
    }
  
    /*  */
  
    var warn$1;
  
    // in some cases, the event used has to be determined at runtime
    // so we used some reserved tokens during compile.
    var RANGE_TOKEN = '__r';
    var CHECKBOX_RADIO_TOKEN = '__c';
  
    function model (
      el,
      dir,
      _warn
    ) {
      warn$1 = _warn;
      var value = dir.value;
      var modifiers = dir.modifiers;
      var tag = el.tag;
      var type = el.attrsMap.type;
  
      {
        // inputs with type="file" are read only and setting the input's
        // value will throw an error.
        if (tag === 'input' && type === 'file') {
          warn$1(
            "<" + (el.tag) + " v-model=\"" + value + "\" type=\"file\">:\n" +
            "File inputs are read only. Use a v-on:change listener instead.",
            el.rawAttrsMap['v-model']
          );
        }
      }
  
      if (el.component) {
        genComponentModel(el, value, modifiers);
        // component v-model doesn't need extra runtime
        return false
      } else if (tag === 'select') {
        genSelect(el, value, modifiers);
      } else if (tag === 'input' && type === 'checkbox') {
        genCheckboxModel(el, value, modifiers);
      } else if (tag === 'input' && type === 'radio') {
        genRadioModel(el, value, modifiers);
      } else if (tag === 'input' || tag === 'textarea') {
        genDefaultModel(el, value, modifiers);
      } else if (!config.isReservedTag(tag)) {
        genComponentModel(el, value, modifiers);
        // component v-model doesn't need extra runtime
        return false
      } else {
        warn$1(
          "<" + (el.tag) + " v-model=\"" + value + "\">: " +
          "v-model is not supported on this element type. " +
          'If you are working with contenteditable, it\'s recommended to ' +
          'wrap a library dedicated for that purpose inside a custom component.',
          el.rawAttrsMap['v-model']
        );
      }
  
      // ensure runtime directive metadata
      return true
    }
  
    function genCheckboxModel (
      el,
      value,
      modifiers
    ) {
      var number = modifiers && modifiers.number;
      var valueBinding = getBindingAttr(el, 'value') || 'null';
      var trueValueBinding = getBindingAttr(el, 'true-value') || 'true';
      var falseValueBinding = getBindingAttr(el, 'false-value') || 'false';
      addProp(el, 'checked',
        "Array.isArray(" + value + ")" +
        "?_i(" + value + "," + valueBinding + ")>-1" + (
          trueValueBinding === 'true'
            ? (":(" + value + ")")
            : (":_q(" + value + "," + trueValueBinding + ")")
        )
      );
      addHandler(el, 'change',
        "var $$a=" + value + "," +
            '$$el=$event.target,' +
            "$$c=$$el.checked?(" + trueValueBinding + "):(" + falseValueBinding + ");" +
        'if(Array.isArray($$a)){' +
          "var $$v=" + (number ? '_n(' + valueBinding + ')' : valueBinding) + "," +
              '$$i=_i($$a,$$v);' +
          "if($$el.checked){$$i<0&&(" + (genAssignmentCode(value, '$$a.concat([$$v])')) + ")}" +
          "else{$$i>-1&&(" + (genAssignmentCode(value, '$$a.slice(0,$$i).concat($$a.slice($$i+1))')) + ")}" +
        "}else{" + (genAssignmentCode(value, '$$c')) + "}",
        null, true
      );
    }
  
    function genRadioModel (
      el,
      value,
      modifiers
    ) {
      var number = modifiers && modifiers.number;
      var valueBinding = getBindingAttr(el, 'value') || 'null';
      valueBinding = number ? ("_n(" + valueBinding + ")") : valueBinding;
      addProp(el, 'checked', ("_q(" + value + "," + valueBinding + ")"));
      addHandler(el, 'change', genAssignmentCode(value, valueBinding), null, true);
    }
  
    function genSelect (
      el,
      value,
      modifiers
    ) {
      var number = modifiers && modifiers.number;
      var selectedVal = "Array.prototype.filter" +
        ".call($event.target.options,function(o){return o.selected})" +
        ".map(function(o){var val = \"_value\" in o ? o._value : o.value;" +
        "return " + (number ? '_n(val)' : 'val') + "})";
  
      var assignment = '$event.target.multiple ? $$selectedVal : $$selectedVal[0]';
      var code = "var $$selectedVal = " + selectedVal + ";";
      code = code + " " + (genAssignmentCode(value, assignment));
      addHandler(el, 'change', code, null, true);
    }
  
    function genDefaultModel (
      el,
      value,
      modifiers
    ) {
      var type = el.attrsMap.type;
  
      // warn if v-bind:value conflicts with v-model
      // except for inputs with v-bind:type
      {
        var value$1 = el.attrsMap['v-bind:value'] || el.attrsMap[':value'];
        var typeBinding = el.attrsMap['v-bind:type'] || el.attrsMap[':type'];
        if (value$1 && !typeBinding) {
          var binding = el.attrsMap['v-bind:value'] ? 'v-bind:value' : ':value';
          warn$1(
            binding + "=\"" + value$1 + "\" conflicts with v-model on the same element " +
            'because the latter already expands to a value binding internally',
            el.rawAttrsMap[binding]
          );
        }
      }
  
      var ref = modifiers || {};
      var lazy = ref.lazy;
      var number = ref.number;
      var trim = ref.trim;
      var needCompositionGuard = !lazy && type !== 'range';
      var event = lazy
        ? 'change'
        : type === 'range'
          ? RANGE_TOKEN
          : 'input';
  
      var valueExpression = '$event.target.value';
      if (trim) {
        valueExpression = "$event.target.value.trim()";
      }
      if (number) {
        valueExpression = "_n(" + valueExpression + ")";
      }
  
      var code = genAssignmentCode(value, valueExpression);
      if (needCompositionGuard) {
        code = "if($event.target.composing)return;" + code;
      }
  
      addProp(el, 'value', ("(" + value + ")"));
      addHandler(el, event, code, null, true);
      if (trim || number) {
        addHandler(el, 'blur', '$forceUpdate()');
      }
    }
  
    /*  */
  
    // normalize v-model event tokens that can only be determined at runtime.
    // it's important to place the event as the first in the array because
    // the whole point is ensuring the v-model callback gets called before
    // user-attached handlers.
    function normalizeEvents (on) {
      /* istanbul ignore if */
      if (isDef(on[RANGE_TOKEN])) {
        // IE input[type=range] only supports `change` event
        var event = isIE ? 'change' : 'input';
        on[event] = [].concat(on[RANGE_TOKEN], on[event] || []);
        delete on[RANGE_TOKEN];
      }
      // This was originally intended to fix #4521 but no longer necessary
      // after 2.5. Keeping it for backwards compat with generated code from < 2.4
      /* istanbul ignore if */
      if (isDef(on[CHECKBOX_RADIO_TOKEN])) {
        on.change = [].concat(on[CHECKBOX_RADIO_TOKEN], on.change || []);
        delete on[CHECKBOX_RADIO_TOKEN];
      }
    }
  
    var target$1;
  
    function createOnceHandler$1 (event, handler, capture) {
      var _target = target$1; // save current target element in closure
      return function onceHandler () {
        var res = handler.apply(null, arguments);
        if (res !== null) {
          remove$2(event, onceHandler, capture, _target);
        }
      }
    }
  
    // #9446: Firefox <= 53 (in particular, ESR 52) has incorrect Event.timeStamp
    // implementation and does not fire microtasks in between event propagation, so
    // safe to exclude.
    var useMicrotaskFix = isUsingMicroTask && !(isFF && Number(isFF[1]) <= 53);
  
    function add$1 (
      name,
      handler,
      capture,
      passive
    ) {
      // async edge case #6566: inner click event triggers patch, event handler
      // attached to outer element during patch, and triggered again. This
      // happens because browsers fire microtask ticks between event propagation.
      // the solution is simple: we save the timestamp when a handler is attached,
      // and the handler would only fire if the event passed to it was fired
      // AFTER it was attached.
      if (useMicrotaskFix) {
        var attachedTimestamp = currentFlushTimestamp;
        var original = handler;
        handler = original._wrapper = function (e) {
          if (
            // no bubbling, should always fire.
            // this is just a safety net in case event.timeStamp is unreliable in
            // certain weird environments...
            e.target === e.currentTarget ||
            // event is fired after handler attachment
            e.timeStamp >= attachedTimestamp ||
            // bail for environments that have buggy event.timeStamp implementations
            // #9462 iOS 9 bug: event.timeStamp is 0 after history.pushState
            // #9681 QtWebEngine event.timeStamp is negative value
            e.timeStamp <= 0 ||
            // #9448 bail if event is fired in another document in a multi-page
            // electron/nw.js app, since event.timeStamp will be using a different
            // starting reference
            e.target.ownerDocument !== document
          ) {
            return original.apply(this, arguments)
          }
        };
      }
      target$1.addEventListener(
        name,
        handler,
        supportsPassive
          ? { capture: capture, passive: passive }
          : capture
      );
    }
  
    function remove$2 (
      name,
      handler,
      capture,
      _target
    ) {
      (_target || target$1).removeEventListener(
        name,
        handler._wrapper || handler,
        capture
      );
    }
  
    function updateDOMListeners (oldVnode, vnode) {
      if (isUndef(oldVnode.data.on) && isUndef(vnode.data.on)) {
        return
      }
      var on = vnode.data.on || {};
      var oldOn = oldVnode.data.on || {};
      target$1 = vnode.elm;
      normalizeEvents(on);
      updateListeners(on, oldOn, add$1, remove$2, createOnceHandler$1, vnode.context);
      target$1 = undefined;
    }
  
    var events = {
      create: updateDOMListeners,
      update: updateDOMListeners
    };
  
    /*  */
  
    var svgContainer;
  
    function updateDOMProps (oldVnode, vnode) {
      if (isUndef(oldVnode.data.domProps) && isUndef(vnode.data.domProps)) {
        return
      }
      var key, cur;
      var elm = vnode.elm;
      var oldProps = oldVnode.data.domProps || {};
      var props = vnode.data.domProps || {};
      // clone observed objects, as the user probably wants to mutate it
      if (isDef(props.__ob__)) {
        props = vnode.data.domProps = extend({}, props);
      }
  
      for (key in oldProps) {
        if (!(key in props)) {
          elm[key] = '';
        }
      }
  
      for (key in props) {
        cur = props[key];
        // ignore children if the node has textContent or innerHTML,
        // as these will throw away existing DOM nodes and cause removal errors
        // on subsequent patches (#3360)
        if (key === 'textContent' || key === 'innerHTML') {
          if (vnode.children) { vnode.children.length = 0; }
          if (cur === oldProps[key]) { continue }
          // #6601 work around Chrome version <= 55 bug where single textNode
          // replaced by innerHTML/textContent retains its parentNode property
          if (elm.childNodes.length === 1) {
            elm.removeChild(elm.childNodes[0]);
          }
        }
  
        if (key === 'value' && elm.tagName !== 'PROGRESS') {
          // store value as _value as well since
          // non-string values will be stringified
          elm._value = cur;
          // avoid resetting cursor position when value is the same
          var strCur = isUndef(cur) ? '' : String(cur);
          if (shouldUpdateValue(elm, strCur)) {
            elm.value = strCur;
          }
        } else if (key === 'innerHTML' && isSVG(elm.tagName) && isUndef(elm.innerHTML)) {
          // IE doesn't support innerHTML for SVG elements
          svgContainer = svgContainer || document.createElement('div');
          svgContainer.innerHTML = "<svg>" + cur + "</svg>";
          var svg = svgContainer.firstChild;
          while (elm.firstChild) {
            elm.removeChild(elm.firstChild);
          }
          while (svg.firstChild) {
            elm.appendChild(svg.firstChild);
          }
        } else if (
          // skip the update if old and new VDOM state is the same.
          // `value` is handled separately because the DOM value may be temporarily
          // out of sync with VDOM state due to focus, composition and modifiers.
          // This  #4521 by skipping the unnecessary `checked` update.
          cur !== oldProps[key]
        ) {
          // some property updates can throw
          // e.g. `value` on <progress> w/ non-finite value
          try {
            elm[key] = cur;
          } catch (e) {}
        }
      }
    }
  
    // check platforms/web/util/attrs.js acceptValue
  
  
    function shouldUpdateValue (elm, checkVal) {
      return (!elm.composing && (
        elm.tagName === 'OPTION' ||
        isNotInFocusAndDirty(elm, checkVal) ||
        isDirtyWithModifiers(elm, checkVal)
      ))
    }
  
    function isNotInFocusAndDirty (elm, checkVal) {
      // return true when textbox (.number and .trim) loses focus and its value is
      // not equal to the updated value
      var notInFocus = true;
      // #6157
      // work around IE bug when accessing document.activeElement in an iframe
      try { notInFocus = document.activeElement !== elm; } catch (e) {}
      return notInFocus && elm.value !== checkVal
    }
  
    function isDirtyWithModifiers (elm, newVal) {
      var value = elm.value;
      var modifiers = elm._vModifiers; // injected by v-model runtime
      if (isDef(modifiers)) {
        if (modifiers.number) {
          return toNumber(value) !== toNumber(newVal)
        }
        if (modifiers.trim) {
          return value.trim() !== newVal.trim()
        }
      }
      return value !== newVal
    }
  
    var domProps = {
      create: updateDOMProps,
      update: updateDOMProps
    };
  
    /*  */
  
    var parseStyleText = cached(function (cssText) {
      var res = {};
      var listDelimiter = /;(?![^(]*\))/g;
      var propertyDelimiter = /:(.+)/;
      cssText.split(listDelimiter).forEach(function (item) {
        if (item) {
          var tmp = item.split(propertyDelimiter);
          tmp.length > 1 && (res[tmp[0].trim()] = tmp[1].trim());
        }
      });
      return res
    });
  
    // merge static and dynamic style data on the same vnode
    function normalizeStyleData (data) {
      var style = normalizeStyleBinding(data.style);
      // static style is pre-processed into an object during compilation
      // and is always a fresh object, so it's safe to merge into it
      return data.staticStyle
        ? extend(data.staticStyle, style)
        : style
    }
  
    // normalize possible array / string values into Object
    function normalizeStyleBinding (bindingStyle) {
      if (Array.isArray(bindingStyle)) {
        return toObject(bindingStyle)
      }
      if (typeof bindingStyle === 'string') {
        return parseStyleText(bindingStyle)
      }
      return bindingStyle
    }
  
    /**
     * parent component style should be after child's
     * so that parent component's style could override it
     */
    function getStyle (vnode, checkChild) {
      var res = {};
      var styleData;
  
      if (checkChild) {
        var childNode = vnode;
        while (childNode.componentInstance) {
          childNode = childNode.componentInstance._vnode;
          if (
            childNode && childNode.data &&
            (styleData = normalizeStyleData(childNode.data))
          ) {
            extend(res, styleData);
          }
        }
      }
  
      if ((styleData = normalizeStyleData(vnode.data))) {
        extend(res, styleData);
      }
  
      var parentNode = vnode;
      while ((parentNode = parentNode.parent)) {
        if (parentNode.data && (styleData = normalizeStyleData(parentNode.data))) {
          extend(res, styleData);
        }
      }
      return res
    }
  
    /*  */
  
    var cssVarRE = /^--/;
    var importantRE = /\s*!important$/;
    var setProp = function (el, name, val) {
      /* istanbul ignore if */
      if (cssVarRE.test(name)) {
        el.style.setProperty(name, val);
      } else if (importantRE.test(val)) {
        el.style.setProperty(hyphenate(name), val.replace(importantRE, ''), 'important');
      } else {
        var normalizedName = normalize(name);
        if (Array.isArray(val)) {
          // Support values array created by autoprefixer, e.g.
          // {display: ["-webkit-box", "-ms-flexbox", "flex"]}
          // Set them one by one, and the browser will only set those it can recognize
          for (var i = 0, len = val.length; i < len; i++) {
            el.style[normalizedName] = val[i];
          }
        } else {
          el.style[normalizedName] = val;
        }
      }
    };
  
    var vendorNames = ['Webkit', 'Moz', 'ms'];
  
    var emptyStyle;
    var normalize = cached(function (prop) {
      emptyStyle = emptyStyle || document.createElement('div').style;
      prop = camelize(prop);
      if (prop !== 'filter' && (prop in emptyStyle)) {
        return prop
      }
      var capName = prop.charAt(0).toUpperCase() + prop.slice(1);
      for (var i = 0; i < vendorNames.length; i++) {
        var name = vendorNames[i] + capName;
        if (name in emptyStyle) {
          return name
        }
      }
    });
  
    function updateStyle (oldVnode, vnode) {
      var data = vnode.data;
      var oldData = oldVnode.data;
  
      if (isUndef(data.staticStyle) && isUndef(data.style) &&
        isUndef(oldData.staticStyle) && isUndef(oldData.style)
      ) {
        return
      }
  
      var cur, name;
      var el = vnode.elm;
      var oldStaticStyle = oldData.staticStyle;
      var oldStyleBinding = oldData.normalizedStyle || oldData.style || {};
  
      // if static style exists, stylebinding already merged into it when doing normalizeStyleData
      var oldStyle = oldStaticStyle || oldStyleBinding;
  
      var style = normalizeStyleBinding(vnode.data.style) || {};
  
      // store normalized style under a different key for next diff
      // make sure to clone it if it's reactive, since the user likely wants
      // to mutate it.
      vnode.data.normalizedStyle = isDef(style.__ob__)
        ? extend({}, style)
        : style;
  
      var newStyle = getStyle(vnode, true);
  
      for (name in oldStyle) {
        if (isUndef(newStyle[name])) {
          setProp(el, name, '');
        }
      }
      for (name in newStyle) {
        cur = newStyle[name];
        if (cur !== oldStyle[name]) {
          // ie9 setting to null has no effect, must use empty string
          setProp(el, name, cur == null ? '' : cur);
        }
      }
    }
  
    var style = {
      create: updateStyle,
      update: updateStyle
    };
  
    /*  */
  
    var whitespaceRE = /\s+/;
  
    /**
     * Add class with compatibility for SVG since classList is not supported on
     * SVG elements in IE
     */
    function addClass (el, cls) {
      /* istanbul ignore if */
      if (!cls || !(cls = cls.trim())) {
        return
      }
  
      /* istanbul ignore else */
      if (el.classList) {
        if (cls.indexOf(' ') > -1) {
          cls.split(whitespaceRE).forEach(function (c) { return el.classList.add(c); });
        } else {
          el.classList.add(cls);
        }
      } else {
        var cur = " " + (el.getAttribute('class') || '') + " ";
        if (cur.indexOf(' ' + cls + ' ') < 0) {
          el.setAttribute('class', (cur + cls).trim());
        }
      }
    }
  
    /**
     * Remove class with compatibility for SVG since classList is not supported on
     * SVG elements in IE
     */
    function removeClass (el, cls) {
      /* istanbul ignore if */
      if (!cls || !(cls = cls.trim())) {
        return
      }
  
      /* istanbul ignore else */
      if (el.classList) {
        if (cls.indexOf(' ') > -1) {
          cls.split(whitespaceRE).forEach(function (c) { return el.classList.remove(c); });
        } else {
          el.classList.remove(cls);
        }
        if (!el.classList.length) {
          el.removeAttribute('class');
        }
      } else {
        var cur = " " + (el.getAttribute('class') || '') + " ";
        var tar = ' ' + cls + ' ';
        while (cur.indexOf(tar) >= 0) {
          cur = cur.replace(tar, ' ');
        }
        cur = cur.trim();
        if (cur) {
          el.setAttribute('class', cur);
        } else {
          el.removeAttribute('class');
        }
      }
    }
  
    /*  */
  
    function resolveTransition (def) {
      if (!def) {
        return
      }
      /* istanbul ignore else */
      if (typeof def === 'object') {
        var res = {};
        if (def.css !== false) {
          extend(res, autoCssTransition(def.name || 'v'));
        }
        extend(res, def);
        return res
      } else if (typeof def === 'string') {
        return autoCssTransition(def)
      }
    }
  
    var autoCssTransition = cached(function (name) {
      return {
        enterClass: (name + "-enter"),
        enterToClass: (name + "-enter-to"),
        enterActiveClass: (name + "-enter-active"),
        leaveClass: (name + "-leave"),
        leaveToClass: (name + "-leave-to"),
        leaveActiveClass: (name + "-leave-active")
      }
    });
  
    var hasTransition = inBrowser && !isIE9;
    var TRANSITION = 'transition';
    var ANIMATION = 'animation';
  
    // Transition property/event sniffing
    var transitionProp = 'transition';
    var transitionEndEvent = 'transitionend';
    var animationProp = 'animation';
    var animationEndEvent = 'animationend';
    if (hasTransition) {
      /* istanbul ignore if */
      if (window.ontransitionend === undefined &&
        window.onwebkittransitionend !== undefined
      ) {
        transitionProp = 'WebkitTransition';
        transitionEndEvent = 'webkitTransitionEnd';
      }
      if (window.onanimationend === undefined &&
        window.onwebkitanimationend !== undefined
      ) {
        animationProp = 'WebkitAnimation';
        animationEndEvent = 'webkitAnimationEnd';
      }
    }
  
    // binding to window is necessary to make hot reload work in IE in strict mode
    var raf = inBrowser
      ? window.requestAnimationFrame
        ? window.requestAnimationFrame.bind(window)
        : setTimeout
      : /* istanbul ignore next */ function (fn) { return fn(); };
  
    function nextFrame (fn) {
      raf(function () {
        raf(fn);
      });
    }
  
    function addTransitionClass (el, cls) {
      var transitionClasses = el._transitionClasses || (el._transitionClasses = []);
      if (transitionClasses.indexOf(cls) < 0) {
        transitionClasses.push(cls);
        addClass(el, cls);
      }
    }
  
    function removeTransitionClass (el, cls) {
      if (el._transitionClasses) {
        remove(el._transitionClasses, cls);
      }
      removeClass(el, cls);
    }
  
    function whenTransitionEnds (
      el,
      expectedType,
      cb
    ) {
      var ref = getTransitionInfo(el, expectedType);
      var type = ref.type;
      var timeout = ref.timeout;
      var propCount = ref.propCount;
      if (!type) { return cb() }
      var event = type === TRANSITION ? transitionEndEvent : animationEndEvent;
      var ended = 0;
      var end = function () {
        el.removeEventListener(event, onEnd);
        cb();
      };
      var onEnd = function (e) {
        if (e.target === el) {
          if (++ended >= propCount) {
            end();
          }
        }
      };
      setTimeout(function () {
        if (ended < propCount) {
          end();
        }
      }, timeout + 1);
      el.addEventListener(event, onEnd);
    }
  
    var transformRE = /\b(transform|all)(,|$)/;
  
    function getTransitionInfo (el, expectedType) {
      var styles = window.getComputedStyle(el);
      // JSDOM may return undefined for transition properties
      var transitionDelays = (styles[transitionProp + 'Delay'] || '').split(', ');
      var transitionDurations = (styles[transitionProp + 'Duration'] || '').split(', ');
      var transitionTimeout = getTimeout(transitionDelays, transitionDurations);
      var animationDelays = (styles[animationProp + 'Delay'] || '').split(', ');
      var animationDurations = (styles[animationProp + 'Duration'] || '').split(', ');
      var animationTimeout = getTimeout(animationDelays, animationDurations);
  
      var type;
      var timeout = 0;
      var propCount = 0;
      /* istanbul ignore if */
      if (expectedType === TRANSITION) {
        if (transitionTimeout > 0) {
          type = TRANSITION;
          timeout = transitionTimeout;
          propCount = transitionDurations.length;
        }
      } else if (expectedType === ANIMATION) {
        if (animationTimeout > 0) {
          type = ANIMATION;
          timeout = animationTimeout;
          propCount = animationDurations.length;
        }
      } else {
        timeout = Math.max(transitionTimeout, animationTimeout);
        type = timeout > 0
          ? transitionTimeout > animationTimeout
            ? TRANSITION
            : ANIMATION
          : null;
        propCount = type
          ? type === TRANSITION
            ? transitionDurations.length
            : animationDurations.length
          : 0;
      }
      var hasTransform =
        type === TRANSITION &&
        transformRE.test(styles[transitionProp + 'Property']);
      return {
        type: type,
        timeout: timeout,
        propCount: propCount,
        hasTransform: hasTransform
      }
    }
  
    function getTimeout (delays, durations) {
      /* istanbul ignore next */
      while (delays.length < durations.length) {
        delays = delays.concat(delays);
      }
  
      return Math.max.apply(null, durations.map(function (d, i) {
        return toMs(d) + toMs(delays[i])
      }))
    }
  
    // Old versions of Chromium (below 61.0.3163.100) formats floating pointer numbers
    // in a locale-dependent way, using a comma instead of a dot.
    // If comma is not replaced with a dot, the input will be rounded down (i.e. acting
    // as a floor function) causing unexpected behaviors
    function toMs (s) {
      return Number(s.slice(0, -1).replace(',', '.')) * 1000
    }
  
    /*  */
  
    function enter (vnode, toggleDisplay) {
      var el = vnode.elm;
  
      // call leave callback now
      if (isDef(el._leaveCb)) {
        el._leaveCb.cancelled = true;
        el._leaveCb();
      }
  
      var data = resolveTransition(vnode.data.transition);
      if (isUndef(data)) {
        return
      }
  
      /* istanbul ignore if */
      if (isDef(el._enterCb) || el.nodeType !== 1) {
        return
      }
  
      var css = data.css;
      var type = data.type;
      var enterClass = data.enterClass;
      var enterToClass = data.enterToClass;
      var enterActiveClass = data.enterActiveClass;
      var appearClass = data.appearClass;
      var appearToClass = data.appearToClass;
      var appearActiveClass = data.appearActiveClass;
      var beforeEnter = data.beforeEnter;
      var enter = data.enter;
      var afterEnter = data.afterEnter;
      var enterCancelled = data.enterCancelled;
      var beforeAppear = data.beforeAppear;
      var appear = data.appear;
      var afterAppear = data.afterAppear;
      var appearCancelled = data.appearCancelled;
      var duration = data.duration;
  
      // activeInstance will always be the <transition> component managing this
      // transition. One edge case to check is when the <transition> is placed
      // as the root node of a child component. In that case we need to check
      // <transition>'s parent for appear check.
      var context = activeInstance;
      var transitionNode = activeInstance.$vnode;
      while (transitionNode && transitionNode.parent) {
        context = transitionNode.context;
        transitionNode = transitionNode.parent;
      }
  
      var isAppear = !context._isMounted || !vnode.isRootInsert;
  
      if (isAppear && !appear && appear !== '') {
        return
      }
  
      var startClass = isAppear && appearClass
        ? appearClass
        : enterClass;
      var activeClass = isAppear && appearActiveClass
        ? appearActiveClass
        : enterActiveClass;
      var toClass = isAppear && appearToClass
        ? appearToClass
        : enterToClass;
  
      var beforeEnterHook = isAppear
        ? (beforeAppear || beforeEnter)
        : beforeEnter;
      var enterHook = isAppear
        ? (typeof appear === 'function' ? appear : enter)
        : enter;
      var afterEnterHook = isAppear
        ? (afterAppear || afterEnter)
        : afterEnter;
      var enterCancelledHook = isAppear
        ? (appearCancelled || enterCancelled)
        : enterCancelled;
  
      var explicitEnterDuration = toNumber(
        isObject(duration)
          ? duration.enter
          : duration
      );
  
      if ( explicitEnterDuration != null) {
        checkDuration(explicitEnterDuration, 'enter', vnode);
      }
  
      var expectsCSS = css !== false && !isIE9;
      var userWantsControl = getHookArgumentsLength(enterHook);
  
      var cb = el._enterCb = once(function () {
        if (expectsCSS) {
          removeTransitionClass(el, toClass);
          removeTransitionClass(el, activeClass);
        }
        if (cb.cancelled) {
          if (expectsCSS) {
            removeTransitionClass(el, startClass);
          }
          enterCancelledHook && enterCancelledHook(el);
        } else {
          afterEnterHook && afterEnterHook(el);
        }
        el._enterCb = null;
      });
  
      if (!vnode.data.show) {
        // remove pending leave element on enter by injecting an insert hook
        mergeVNodeHook(vnode, 'insert', function () {
          var parent = el.parentNode;
          var pendingNode = parent && parent._pending && parent._pending[vnode.key];
          if (pendingNode &&
            pendingNode.tag === vnode.tag &&
            pendingNode.elm._leaveCb
          ) {
            pendingNode.elm._leaveCb();
          }
          enterHook && enterHook(el, cb);
        });
      }
  
      // start enter transition
      beforeEnterHook && beforeEnterHook(el);
      if (expectsCSS) {
        addTransitionClass(el, startClass);
        addTransitionClass(el, activeClass);
        nextFrame(function () {
          removeTransitionClass(el, startClass);
          if (!cb.cancelled) {
            addTransitionClass(el, toClass);
            if (!userWantsControl) {
              if (isValidDuration(explicitEnterDuration)) {
                setTimeout(cb, explicitEnterDuration);
              } else {
                whenTransitionEnds(el, type, cb);
              }
            }
          }
        });
      }
  
      if (vnode.data.show) {
        toggleDisplay && toggleDisplay();
        enterHook && enterHook(el, cb);
      }
  
      if (!expectsCSS && !userWantsControl) {
        cb();
      }
    }
  
    function leave (vnode, rm) {
      var el = vnode.elm;
  
      // call enter callback now
      if (isDef(el._enterCb)) {
        el._enterCb.cancelled = true;
        el._enterCb();
      }
  
      var data = resolveTransition(vnode.data.transition);
      if (isUndef(data) || el.nodeType !== 1) {
        return rm()
      }
  
      /* istanbul ignore if */
      if (isDef(el._leaveCb)) {
        return
      }
  
      var css = data.css;
      var type = data.type;
      var leaveClass = data.leaveClass;
      var leaveToClass = data.leaveToClass;
      var leaveActiveClass = data.leaveActiveClass;
      var beforeLeave = data.beforeLeave;
      var leave = data.leave;
      var afterLeave = data.afterLeave;
      var leaveCancelled = data.leaveCancelled;
      var delayLeave = data.delayLeave;
      var duration = data.duration;
  
      var expectsCSS = css !== false && !isIE9;
      var userWantsControl = getHookArgumentsLength(leave);
  
      var explicitLeaveDuration = toNumber(
        isObject(duration)
          ? duration.leave
          : duration
      );
  
      if ( isDef(explicitLeaveDuration)) {
        checkDuration(explicitLeaveDuration, 'leave', vnode);
      }
  
      var cb = el._leaveCb = once(function () {
        if (el.parentNode && el.parentNode._pending) {
          el.parentNode._pending[vnode.key] = null;
        }
        if (expectsCSS) {
          removeTransitionClass(el, leaveToClass);
          removeTransitionClass(el, leaveActiveClass);
        }
        if (cb.cancelled) {
          if (expectsCSS) {
            removeTransitionClass(el, leaveClass);
          }
          leaveCancelled && leaveCancelled(el);
        } else {
          rm();
          afterLeave && afterLeave(el);
        }
        el._leaveCb = null;
      });
  
      if (delayLeave) {
        delayLeave(performLeave);
      } else {
        performLeave();
      }
  
      function performLeave () {
        // the delayed leave may have already been cancelled
        if (cb.cancelled) {
          return
        }
        // record leaving element
        if (!vnode.data.show && el.parentNode) {
          (el.parentNode._pending || (el.parentNode._pending = {}))[(vnode.key)] = vnode;
        }
        beforeLeave && beforeLeave(el);
        if (expectsCSS) {
          addTransitionClass(el, leaveClass);
          addTransitionClass(el, leaveActiveClass);
          nextFrame(function () {
            removeTransitionClass(el, leaveClass);
            if (!cb.cancelled) {
              addTransitionClass(el, leaveToClass);
              if (!userWantsControl) {
                if (isValidDuration(explicitLeaveDuration)) {
                  setTimeout(cb, explicitLeaveDuration);
                } else {
                  whenTransitionEnds(el, type, cb);
                }
              }
            }
          });
        }
        leave && leave(el, cb);
        if (!expectsCSS && !userWantsControl) {
          cb();
        }
      }
    }
  
    // only used in dev mode
    function checkDuration (val, name, vnode) {
      if (typeof val !== 'number') {
        warn(
          "<transition> explicit " + name + " duration is not a valid number - " +
          "got " + (JSON.stringify(val)) + ".",
          vnode.context
        );
      } else if (isNaN(val)) {
        warn(
          "<transition> explicit " + name + " duration is NaN - " +
          'the duration expression might be incorrect.',
          vnode.context
        );
      }
    }
  
    function isValidDuration (val) {
      return typeof val === 'number' && !isNaN(val)
    }
  
    /**
     * Normalize a transition hook's argument length. The hook may be:
     * - a merged hook (invoker) with the original in .fns
     * - a wrapped component method (check ._length)
     * - a plain function (.length)
     */
    function getHookArgumentsLength (fn) {
      if (isUndef(fn)) {
        return false
      }
      var invokerFns = fn.fns;
      if (isDef(invokerFns)) {
        // invoker
        return getHookArgumentsLength(
          Array.isArray(invokerFns)
            ? invokerFns[0]
            : invokerFns
        )
      } else {
        return (fn._length || fn.length) > 1
      }
    }
  
    function _enter (_, vnode) {
      if (vnode.data.show !== true) {
        enter(vnode);
      }
    }
  
    var transition = inBrowser ? {
      create: _enter,
      activate: _enter,
      remove: function remove (vnode, rm) {
        /* istanbul ignore else */
        if (vnode.data.show !== true) {
          leave(vnode, rm);
        } else {
          rm();
        }
      }
    } : {};
  
    var platformModules = [
      attrs,
      klass,
      events,
      domProps,
      style,
      transition
    ];
  
    /*  */
  
    // the directive module should be applied last, after all
    // built-in modules have been applied.
    var modules = platformModules.concat(baseModules);
  
    var patch = createPatchFunction({ nodeOps: nodeOps, modules: modules });
  
    /**
     * Not type checking this file because flow doesn't like attaching
     * properties to Elements.
     */
  
    /* istanbul ignore if */
    if (isIE9) {
      // http://www.matts411.com/post/internet-explorer-9-oninput/
      document.addEventListener('selectionchange', function () {
        var el = document.activeElement;
        if (el && el.vmodel) {
          trigger(el, 'input');
        }
      });
    }
  
    var directive = {
      inserted: function inserted (el, binding, vnode, oldVnode) {
        if (vnode.tag === 'select') {
          // #6903
          if (oldVnode.elm && !oldVnode.elm._vOptions) {
            mergeVNodeHook(vnode, 'postpatch', function () {
              directive.componentUpdated(el, binding, vnode);
            });
          } else {
            setSelected(el, binding, vnode.context);
          }
          el._vOptions = [].map.call(el.options, getValue);
        } else if (vnode.tag === 'textarea' || isTextInputType(el.type)) {
          el._vModifiers = binding.modifiers;
          if (!binding.modifiers.lazy) {
            el.addEventListener('compositionstart', onCompositionStart);
            el.addEventListener('compositionend', onCompositionEnd);
            // Safari < 10.2 & UIWebView doesn't fire compositionend when
            // switching focus before confirming composition choice
            // this also fixes the issue where some browsers e.g. iOS Chrome
            // fires "change" instead of "input" on autocomplete.
            el.addEventListener('change', onCompositionEnd);
            /* istanbul ignore if */
            if (isIE9) {
              el.vmodel = true;
            }
          }
        }
      },
  
      componentUpdated: function componentUpdated (el, binding, vnode) {
        if (vnode.tag === 'select') {
          setSelected(el, binding, vnode.context);
          // in case the options rendered by v-for have changed,
          // it's possible that the value is out-of-sync with the rendered options.
          // detect such cases and filter out values that no longer has a matching
          // option in the DOM.
          var prevOptions = el._vOptions;
          var curOptions = el._vOptions = [].map.call(el.options, getValue);
          if (curOptions.some(function (o, i) { return !looseEqual(o, prevOptions[i]); })) {
            // trigger change event if
            // no matching option found for at least one value
            var needReset = el.multiple
              ? binding.value.some(function (v) { return hasNoMatchingOption(v, curOptions); })
              : binding.value !== binding.oldValue && hasNoMatchingOption(binding.value, curOptions);
            if (needReset) {
              trigger(el, 'change');
            }
          }
        }
      }
    };
  
    function setSelected (el, binding, vm) {
      actuallySetSelected(el, binding, vm);
      /* istanbul ignore if */
      if (isIE || isEdge) {
        setTimeout(function () {
          actuallySetSelected(el, binding, vm);
        }, 0);
      }
    }
  
    function actuallySetSelected (el, binding, vm) {
      var value = binding.value;
      var isMultiple = el.multiple;
      if (isMultiple && !Array.isArray(value)) {
         warn(
          "<select multiple v-model=\"" + (binding.expression) + "\"> " +
          "expects an Array value for its binding, but got " + (Object.prototype.toString.call(value).slice(8, -1)),
          vm
        );
        return
      }
      var selected, option;
      for (var i = 0, l = el.options.length; i < l; i++) {
        option = el.options[i];
        if (isMultiple) {
          selected = looseIndexOf(value, getValue(option)) > -1;
          if (option.selected !== selected) {
            option.selected = selected;
          }
        } else {
          if (looseEqual(getValue(option), value)) {
            if (el.selectedIndex !== i) {
              el.selectedIndex = i;
            }
            return
          }
        }
      }
      if (!isMultiple) {
        el.selectedIndex = -1;
      }
    }
  
    function hasNoMatchingOption (value, options) {
      return options.every(function (o) { return !looseEqual(o, value); })
    }
  
    function getValue (option) {
      return '_value' in option
        ? option._value
        : option.value
    }
  
    function onCompositionStart (e) {
      e.target.composing = true;
    }
  
    function onCompositionEnd (e) {
      // prevent triggering an input event for no reason
      if (!e.target.composing) { return }
      e.target.composing = false;
      trigger(e.target, 'input');
    }
  
    function trigger (el, type) {
      var e = document.createEvent('HTMLEvents');
      e.initEvent(type, true, true);
      el.dispatchEvent(e);
    }
  
    /*  */
  
    // recursively search for possible transition defined inside the component root
    function locateNode (vnode) {
      return vnode.componentInstance && (!vnode.data || !vnode.data.transition)
        ? locateNode(vnode.componentInstance._vnode)
        : vnode
    }
  
    var show = {
      bind: function bind (el, ref, vnode) {
        var value = ref.value;
  
        vnode = locateNode(vnode);
        var transition = vnode.data && vnode.data.transition;
        var originalDisplay = el.__vOriginalDisplay =
          el.style.display === 'none' ? '' : el.style.display;
        if (value && transition) {
          vnode.data.show = true;
          enter(vnode, function () {
            el.style.display = originalDisplay;
          });
        } else {
          el.style.display = value ? originalDisplay : 'none';
        }
      },
  
      update: function update (el, ref, vnode) {
        var value = ref.value;
        var oldValue = ref.oldValue;
  
        /* istanbul ignore if */
        if (!value === !oldValue) { return }
        vnode = locateNode(vnode);
        var transition = vnode.data && vnode.data.transition;
        if (transition) {
          vnode.data.show = true;
          if (value) {
            enter(vnode, function () {
              el.style.display = el.__vOriginalDisplay;
            });
          } else {
            leave(vnode, function () {
              el.style.display = 'none';
            });
          }
        } else {
          el.style.display = value ? el.__vOriginalDisplay : 'none';
        }
      },
  
      unbind: function unbind (
        el,
        binding,
        vnode,
        oldVnode,
        isDestroy
      ) {
        if (!isDestroy) {
          el.style.display = el.__vOriginalDisplay;
        }
      }
    };
  
    var platformDirectives = {
      model: directive,
      show: show
    };
  
    /*  */
  
    var transitionProps = {
      name: String,
      appear: Boolean,
      css: Boolean,
      mode: String,
      type: String,
      enterClass: String,
      leaveClass: String,
      enterToClass: String,
      leaveToClass: String,
      enterActiveClass: String,
      leaveActiveClass: String,
      appearClass: String,
      appearActiveClass: String,
      appearToClass: String,
      duration: [Number, String, Object]
    };
  
    // in case the child is also an abstract component, e.g. <keep-alive>
    // we want to recursively retrieve the real component to be rendered
    function getRealChild (vnode) {
      var compOptions = vnode && vnode.componentOptions;
      if (compOptions && compOptions.Ctor.options.abstract) {
        return getRealChild(getFirstComponentChild(compOptions.children))
      } else {
        return vnode
      }
    }
  
    function extractTransitionData (comp) {
      var data = {};
      var options = comp.$options;
      // props
      for (var key in options.propsData) {
        data[key] = comp[key];
      }
      // events.
      // extract listeners and pass them directly to the transition methods
      var listeners = options._parentListeners;
      for (var key$1 in listeners) {
        data[camelize(key$1)] = listeners[key$1];
      }
      return data
    }
  
    function placeholder (h, rawChild) {
      if (/\d-keep-alive$/.test(rawChild.tag)) {
        return h('keep-alive', {
          props: rawChild.componentOptions.propsData
        })
      }
    }
  
    function hasParentTransition (vnode) {
      while ((vnode = vnode.parent)) {
        if (vnode.data.transition) {
          return true
        }
      }
    }
  
    function isSameChild (child, oldChild) {
      return oldChild.key === child.key && oldChild.tag === child.tag
    }
  
    var isNotTextNode = function (c) { return c.tag || isAsyncPlaceholder(c); };
  
    var isVShowDirective = function (d) { return d.name === 'show'; };
  
    var Transition = {
      name: 'transition',
      props: transitionProps,
      abstract: true,
  
      render: function render (h) {
        var this$1 = this;
  
        var children = this.$slots.default;
        if (!children) {
          return
        }
  
        // filter out text nodes (possible whitespaces)
        children = children.filter(isNotTextNode);
        /* istanbul ignore if */
        if (!children.length) {
          return
        }
  
        // warn multiple elements
        if ( children.length > 1) {
          warn(
            '<transition> can only be used on a single element. Use ' +
            '<transition-group> for lists.',
            this.$parent
          );
        }
  
        var mode = this.mode;
  
        // warn invalid mode
        if (
          mode && mode !== 'in-out' && mode !== 'out-in'
        ) {
          warn(
            'invalid <transition> mode: ' + mode,
            this.$parent
          );
        }
  
        var rawChild = children[0];
  
        // if this is a component root node and the component's
        // parent container node also has transition, skip.
        if (hasParentTransition(this.$vnode)) {
          return rawChild
        }
  
        // apply transition data to child
        // use getRealChild() to ignore abstract components e.g. keep-alive
        var child = getRealChild(rawChild);
        /* istanbul ignore if */
        if (!child) {
          return rawChild
        }
  
        if (this._leaving) {
          return placeholder(h, rawChild)
        }
  
        // ensure a key that is unique to the vnode type and to this transition
        // component instance. This key will be used to remove pending leaving nodes
        // during entering.
        var id = "__transition-" + (this._uid) + "-";
        child.key = child.key == null
          ? child.isComment
            ? id + 'comment'
            : id + child.tag
          : isPrimitive(child.key)
            ? (String(child.key).indexOf(id) === 0 ? child.key : id + child.key)
            : child.key;
  
        var data = (child.data || (child.data = {})).transition = extractTransitionData(this);
        var oldRawChild = this._vnode;
        var oldChild = getRealChild(oldRawChild);
  
        // mark v-show
        // so that the transition module can hand over the control to the directive
        if (child.data.directives && child.data.directives.some(isVShowDirective)) {
          child.data.show = true;
        }
  
        if (
          oldChild &&
          oldChild.data &&
          !isSameChild(child, oldChild) &&
          !isAsyncPlaceholder(oldChild) &&
          // #6687 component root is a comment node
          !(oldChild.componentInstance && oldChild.componentInstance._vnode.isComment)
        ) {
          // replace old child transition data with fresh one
          // important for dynamic transitions!
          var oldData = oldChild.data.transition = extend({}, data);
          // handle transition mode
          if (mode === 'out-in') {
            // return placeholder node and queue update when leave finishes
            this._leaving = true;
            mergeVNodeHook(oldData, 'afterLeave', function () {
              this$1._leaving = false;
              this$1.$forceUpdate();
            });
            return placeholder(h, rawChild)
          } else if (mode === 'in-out') {
            if (isAsyncPlaceholder(child)) {
              return oldRawChild
            }
            var delayedLeave;
            var performLeave = function () { delayedLeave(); };
            mergeVNodeHook(data, 'afterEnter', performLeave);
            mergeVNodeHook(data, 'enterCancelled', performLeave);
            mergeVNodeHook(oldData, 'delayLeave', function (leave) { delayedLeave = leave; });
          }
        }
  
        return rawChild
      }
    };
  
    /*  */
  
    var props = extend({
      tag: String,
      moveClass: String
    }, transitionProps);
  
    delete props.mode;
  
    var TransitionGroup = {
      props: props,
  
      beforeMount: function beforeMount () {
        var this$1 = this;
  
        var update = this._update;
        this._update = function (vnode, hydrating) {
          var restoreActiveInstance = setActiveInstance(this$1);
          // force removing pass
          this$1.__patch__(
            this$1._vnode,
            this$1.kept,
            false, // hydrating
            true // removeOnly (!important, avoids unnecessary moves)
          );
          this$1._vnode = this$1.kept;
          restoreActiveInstance();
          update.call(this$1, vnode, hydrating);
        };
      },
  
      render: function render (h) {
        var tag = this.tag || this.$vnode.data.tag || 'span';
        var map = Object.create(null);
        var prevChildren = this.prevChildren = this.children;
        var rawChildren = this.$slots.default || [];
        var children = this.children = [];
        var transitionData = extractTransitionData(this);
  
        for (var i = 0; i < rawChildren.length; i++) {
          var c = rawChildren[i];
          if (c.tag) {
            if (c.key != null && String(c.key).indexOf('__vlist') !== 0) {
              children.push(c);
              map[c.key] = c
              ;(c.data || (c.data = {})).transition = transitionData;
            } else {
              var opts = c.componentOptions;
              var name = opts ? (opts.Ctor.options.name || opts.tag || '') : c.tag;
              warn(("<transition-group> children must be keyed: <" + name + ">"));
            }
          }
        }
  
        if (prevChildren) {
          var kept = [];
          var removed = [];
          for (var i$1 = 0; i$1 < prevChildren.length; i$1++) {
            var c$1 = prevChildren[i$1];
            c$1.data.transition = transitionData;
            c$1.data.pos = c$1.elm.getBoundingClientRect();
            if (map[c$1.key]) {
              kept.push(c$1);
            } else {
              removed.push(c$1);
            }
          }
          this.kept = h(tag, null, kept);
          this.removed = removed;
        }
  
        return h(tag, null, children)
      },
  
      updated: function updated () {
        var children = this.prevChildren;
        var moveClass = this.moveClass || ((this.name || 'v') + '-move');
        if (!children.length || !this.hasMove(children[0].elm, moveClass)) {
          return
        }
  
        // we divide the work into three loops to avoid mixing DOM reads and writes
        // in each iteration - which helps prevent layout thrashing.
        children.forEach(callPendingCbs);
        children.forEach(recordPosition);
        children.forEach(applyTranslation);
  
        // force reflow to put everything in position
        // assign to this to avoid being removed in tree-shaking
        // $flow-disable-line
        this._reflow = document.body.offsetHeight;
  
        children.forEach(function (c) {
          if (c.data.moved) {
            var el = c.elm;
            var s = el.style;
            addTransitionClass(el, moveClass);
            s.transform = s.WebkitTransform = s.transitionDuration = '';
            el.addEventListener(transitionEndEvent, el._moveCb = function cb (e) {
              if (e && e.target !== el) {
                return
              }
              if (!e || /transform$/.test(e.propertyName)) {
                el.removeEventListener(transitionEndEvent, cb);
                el._moveCb = null;
                removeTransitionClass(el, moveClass);
              }
            });
          }
        });
      },
  
      methods: {
        hasMove: function hasMove (el, moveClass) {
          /* istanbul ignore if */
          if (!hasTransition) {
            return false
          }
          /* istanbul ignore if */
          if (this._hasMove) {
            return this._hasMove
          }
          // Detect whether an element with the move class applied has
          // CSS transitions. Since the element may be inside an entering
          // transition at this very moment, we make a clone of it and remove
          // all other transition classes applied to ensure only the move class
          // is applied.
          var clone = el.cloneNode();
          if (el._transitionClasses) {
            el._transitionClasses.forEach(function (cls) { removeClass(clone, cls); });
          }
          addClass(clone, moveClass);
          clone.style.display = 'none';
          this.$el.appendChild(clone);
          var info = getTransitionInfo(clone);
          this.$el.removeChild(clone);
          return (this._hasMove = info.hasTransform)
        }
      }
    };
  
    function callPendingCbs (c) {
      /* istanbul ignore if */
      if (c.elm._moveCb) {
        c.elm._moveCb();
      }
      /* istanbul ignore if */
      if (c.elm._enterCb) {
        c.elm._enterCb();
      }
    }
  
    function recordPosition (c) {
      c.data.newPos = c.elm.getBoundingClientRect();
    }
  
    function applyTranslation (c) {
      var oldPos = c.data.pos;
      var newPos = c.data.newPos;
      var dx = oldPos.left - newPos.left;
      var dy = oldPos.top - newPos.top;
      if (dx || dy) {
        c.data.moved = true;
        var s = c.elm.style;
        s.transform = s.WebkitTransform = "translate(" + dx + "px," + dy + "px)";
        s.transitionDuration = '0s';
      }
    }
  
    var platformComponents = {
      Transition: Transition,
      TransitionGroup: TransitionGroup
    };
  
    /*  */
  
    // install platform specific utils
    Vue.config.mustUseProp = mustUseProp;
    Vue.config.isReservedTag = isReservedTag;
    Vue.config.isReservedAttr = isReservedAttr;
    Vue.config.getTagNamespace = getTagNamespace;
    Vue.config.isUnknownElement = isUnknownElement;
  
    // install platform runtime directives & components
    extend(Vue.options.directives, platformDirectives);
    extend(Vue.options.components, platformComponents);
  
    // install platform patch function
    // 安装平台特有的patch函数， diff发生的地方
    Vue.prototype.__patch__ = inBrowser ? patch : noop;
  
    // public mount method
    // 实现$mount: 挂载组件
    Vue.prototype.$mount = function (
      el,
      hydrating
    ) {
      // 获取el元素 
      el = el && inBrowser ? query(el) : undefined;
      return mountComponent(this, el, hydrating)
    };
  
    // devtools global hook
    /* istanbul ignore next */
    if (inBrowser) {
      setTimeout(function () {
        if (config.devtools) {
          if (devtools) {
            devtools.emit('init', Vue);
          } else {
            console[console.info ? 'info' : 'log'](
              'Download the Vue Devtools extension for a better development experience:\n' +
              'https://github.com/vuejs/vue-devtools'
            );
          }
        }
        if (
          config.productionTip !== false &&
          typeof console !== 'undefined'
        ) {
          console[console.info ? 'info' : 'log'](
            "You are running Vue in development mode.\n" +
            "Make sure to turn on production mode when deploying for production.\n" +
            "See more tips at https://vuejs.org/guide/deployment.html"
          );
        }
      }, 0);
    }
  
    /*  */
  
    var defaultTagRE = /\{\{((?:.|\r?\n)+?)\}\}/g;
    var regexEscapeRE = /[-.*+?^${}()|[\]\/\\]/g;
  
    var buildRegex = cached(function (delimiters) {
      var open = delimiters[0].replace(regexEscapeRE, '\\$&');
      var close = delimiters[1].replace(regexEscapeRE, '\\$&');
      return new RegExp(open + '((?:.|\\n)+?)' + close, 'g')
    });
  
  
  
    function parseText (
      text,
      delimiters
    ) {
      var tagRE = delimiters ? buildRegex(delimiters) : defaultTagRE;
      if (!tagRE.test(text)) {
        return
      }
      var tokens = [];
      var rawTokens = [];
      var lastIndex = tagRE.lastIndex = 0;
      var match, index, tokenValue;
      while ((match = tagRE.exec(text))) {
        index = match.index;
        // push text token
        if (index > lastIndex) {
          rawTokens.push(tokenValue = text.slice(lastIndex, index));
          tokens.push(JSON.stringify(tokenValue));
        }
        // tag token
        var exp = parseFilters(match[1].trim());
        tokens.push(("_s(" + exp + ")"));
        rawTokens.push({ '@binding': exp });
        lastIndex = index + match[0].length;
      }
      if (lastIndex < text.length) {
        rawTokens.push(tokenValue = text.slice(lastIndex));
        tokens.push(JSON.stringify(tokenValue));
      }
      return {
        expression: tokens.join('+'),
        tokens: rawTokens
      }
    }
  
    /*  */
  
    function transformNode (el, options) {
      var warn = options.warn || baseWarn;
      var staticClass = getAndRemoveAttr(el, 'class');
      if ( staticClass) {
        var res = parseText(staticClass, options.delimiters);
        if (res) {
          warn(
            "class=\"" + staticClass + "\": " +
            'Interpolation inside attributes has been removed. ' +
            'Use v-bind or the colon shorthand instead. For example, ' +
            'instead of <div class="{{ val }}">, use <div :class="val">.',
            el.rawAttrsMap['class']
          );
        }
      }
      if (staticClass) {
        el.staticClass = JSON.stringify(staticClass);
      }
      var classBinding = getBindingAttr(el, 'class', false /* getStatic */);
      if (classBinding) {
        el.classBinding = classBinding;
      }
    }
  
    function genData (el) {
      var data = '';
      if (el.staticClass) {
        data += "staticClass:" + (el.staticClass) + ",";
      }
      if (el.classBinding) {
        data += "class:" + (el.classBinding) + ",";
      }
      return data
    }
  
    var klass$1 = {
      staticKeys: ['staticClass'],
      transformNode: transformNode,
      genData: genData
    };
  
    /*  */
  
    function transformNode$1 (el, options) {
      var warn = options.warn || baseWarn;
      var staticStyle = getAndRemoveAttr(el, 'style');
      if (staticStyle) {
        /* istanbul ignore if */
        {
          var res = parseText(staticStyle, options.delimiters);
          if (res) {
            warn(
              "style=\"" + staticStyle + "\": " +
              'Interpolation inside attributes has been removed. ' +
              'Use v-bind or the colon shorthand instead. For example, ' +
              'instead of <div style="{{ val }}">, use <div :style="val">.',
              el.rawAttrsMap['style']
            );
          }
        }
        el.staticStyle = JSON.stringify(parseStyleText(staticStyle));
      }
  
      var styleBinding = getBindingAttr(el, 'style', false /* getStatic */);
      if (styleBinding) {
        el.styleBinding = styleBinding;
      }
    }
  
    function genData$1 (el) {
      var data = '';
      if (el.staticStyle) {
        data += "staticStyle:" + (el.staticStyle) + ",";
      }
      if (el.styleBinding) {
        data += "style:(" + (el.styleBinding) + "),";
      }
      return data
    }
  
    var style$1 = {
      staticKeys: ['staticStyle'],
      transformNode: transformNode$1,
      genData: genData$1
    };
  
    /*  */
  
    var decoder;
  
    var he = {
      decode: function decode (html) {
        decoder = decoder || document.createElement('div');
        decoder.innerHTML = html;
        return decoder.textContent
      }
    };
  
    /*  */
  
    var isUnaryTag = makeMap(
      'area,base,br,col,embed,frame,hr,img,input,isindex,keygen,' +
      'link,meta,param,source,track,wbr'
    );
  
    // Elements that you can, intentionally, leave open
    // (and which close themselves)
    var canBeLeftOpenTag = makeMap(
      'colgroup,dd,dt,li,options,p,td,tfoot,th,thead,tr,source'
    );
  
    // HTML5 tags https://html.spec.whatwg.org/multipage/indices.html#elements-3
    // Phrasing Content https://html.spec.whatwg.org/multipage/dom.html#phrasing-content
    var isNonPhrasingTag = makeMap(
      'address,article,aside,base,blockquote,body,caption,col,colgroup,dd,' +
      'details,dialog,div,dl,dt,fieldset,figcaption,figure,footer,form,' +
      'h1,h2,h3,h4,h5,h6,head,header,hgroup,hr,html,legend,li,menuitem,meta,' +
      'optgroup,option,param,rp,rt,source,style,summary,tbody,td,tfoot,th,thead,' +
      'title,tr,track'
    );
  
    /**
     * Not type-checking this file because it's mostly vendor code.
     */
  
    // Regular Expressions for parsing tags and attributes
    var attribute = /^\s*([^\s"'<>\/=]+)(?:\s*(=)\s*(?:"([^"]*)"+|'([^']*)'+|([^\s"'=<>`]+)))?/;
    var dynamicArgAttribute = /^\s*((?:v-[\w-]+:|@|:|#)\[[^=]+\][^\s"'<>\/=]*)(?:\s*(=)\s*(?:"([^"]*)"+|'([^']*)'+|([^\s"'=<>`]+)))?/;
    var ncname = "[a-zA-Z_][\\-\\.0-9_a-zA-Z" + (unicodeRegExp.source) + "]*";
    var qnameCapture = "((?:" + ncname + "\\:)?" + ncname + ")";
    var startTagOpen = new RegExp(("^<" + qnameCapture));
    var startTagClose = /^\s*(\/?)>/;
    var endTag = new RegExp(("^<\\/" + qnameCapture + "[^>]*>"));
    var doctype = /^<!DOCTYPE [^>]+>/i;
    // #7298: escape - to avoid being passed as HTML comment when inlined in page
    var comment = /^<!\--/;
    var conditionalComment = /^<!\[/;
  
    // Special Elements (can contain anything)
    var isPlainTextElement = makeMap('script,style,textarea', true);
    var reCache = {};
  
    var decodingMap = {
      '&lt;': '<',
      '&gt;': '>',
      '&quot;': '"',
      '&amp;': '&',
      '&#10;': '\n',
      '&#9;': '\t',
      '&#39;': "'"
    };
    var encodedAttr = /&(?:lt|gt|quot|amp|#39);/g;
    var encodedAttrWithNewLines = /&(?:lt|gt|quot|amp|#39|#10|#9);/g;
  
    // #5992
    var isIgnoreNewlineTag = makeMap('pre,textarea', true);
    var shouldIgnoreFirstNewline = function (tag, html) { return tag && isIgnoreNewlineTag(tag) && html[0] === '\n'; };
  
    function decodeAttr (value, shouldDecodeNewlines) {
      var re = shouldDecodeNewlines ? encodedAttrWithNewLines : encodedAttr;
      return value.replace(re, function (match) { return decodingMap[match]; })
    }
  
    function parseHTML (html, options) {
      var stack = [];
      var expectHTML = options.expectHTML;
      var isUnaryTag = options.isUnaryTag || no;
      var canBeLeftOpenTag = options.canBeLeftOpenTag || no;
      var index = 0;
      var last, lastTag;
      while (html) {
        last = html;
        // Make sure we're not in a plaintext content element like script/style
        if (!lastTag || !isPlainTextElement(lastTag)) {
          var textEnd = html.indexOf('<');
          if (textEnd === 0) {
            // Comment:
            if (comment.test(html)) {
              var commentEnd = html.indexOf('-->');
  
              if (commentEnd >= 0) {
                if (options.shouldKeepComment) {
                  options.comment(html.substring(4, commentEnd), index, index + commentEnd + 3);
                }
                advance(commentEnd + 3);
                continue
              }
            }
  
            // http://en.wikipedia.org/wiki/Conditional_comment#Downlevel-revealed_conditional_comment
            if (conditionalComment.test(html)) {
              var conditionalEnd = html.indexOf(']>');
  
              if (conditionalEnd >= 0) {
                advance(conditionalEnd + 2);
                continue
              }
            }
  
            // Doctype:
            var doctypeMatch = html.match(doctype);
            if (doctypeMatch) {
              advance(doctypeMatch[0].length);
              continue
            }
  
            // End tag:
            var endTagMatch = html.match(endTag);
            if (endTagMatch) {
              var curIndex = index;
              advance(endTagMatch[0].length);
              parseEndTag(endTagMatch[1], curIndex, index);
              continue
            }
  
            // Start tag:
            var startTagMatch = parseStartTag();
            if (startTagMatch) {
              handleStartTag(startTagMatch);
              if (shouldIgnoreFirstNewline(startTagMatch.tagName, html)) {
                advance(1);
              }
              continue
            }
          }
  
          var text = (void 0), rest = (void 0), next = (void 0);
          if (textEnd >= 0) {
            rest = html.slice(textEnd);
            while (
              !endTag.test(rest) &&
              !startTagOpen.test(rest) &&
              !comment.test(rest) &&
              !conditionalComment.test(rest)
            ) {
              // < in plain text, be forgiving and treat it as text
              next = rest.indexOf('<', 1);
              if (next < 0) { break }
              textEnd += next;
              rest = html.slice(textEnd);
            }
            text = html.substring(0, textEnd);
          }
  
          if (textEnd < 0) {
            text = html;
          }
  
          if (text) {
            advance(text.length);
          }
  
          if (options.chars && text) {
            options.chars(text, index - text.length, index);
          }
        } else {
          var endTagLength = 0;
          var stackedTag = lastTag.toLowerCase();
          var reStackedTag = reCache[stackedTag] || (reCache[stackedTag] = new RegExp('([\\s\\S]*?)(</' + stackedTag + '[^>]*>)', 'i'));
          var rest$1 = html.replace(reStackedTag, function (all, text, endTag) {
            endTagLength = endTag.length;
            if (!isPlainTextElement(stackedTag) && stackedTag !== 'noscript') {
              text = text
                .replace(/<!\--([\s\S]*?)-->/g, '$1') // #7298
                .replace(/<!\[CDATA\[([\s\S]*?)]]>/g, '$1');
            }
            if (shouldIgnoreFirstNewline(stackedTag, text)) {
              text = text.slice(1);
            }
            if (options.chars) {
              options.chars(text);
            }
            return ''
          });
          index += html.length - rest$1.length;
          html = rest$1;
          parseEndTag(stackedTag, index - endTagLength, index);
        }
  
        if (html === last) {
          options.chars && options.chars(html);
          if ( !stack.length && options.warn) {
            options.warn(("Mal-formatted tag at end of template: \"" + html + "\""), { start: index + html.length });
          }
          break
        }
      }
  
      // Clean up any remaining tags
      parseEndTag();
  
      function advance (n) {
        index += n;
        html = html.substring(n);
      }
  
      function parseStartTag () {
        var start = html.match(startTagOpen);
        if (start) {
          var match = {
            tagName: start[1],
            attrs: [],
            start: index
          };
          advance(start[0].length);
          var end, attr;
          while (!(end = html.match(startTagClose)) && (attr = html.match(dynamicArgAttribute) || html.match(attribute))) {
            attr.start = index;
            advance(attr[0].length);
            attr.end = index;
            match.attrs.push(attr);
          }
          if (end) {
            match.unarySlash = end[1];
            advance(end[0].length);
            match.end = index;
            return match
          }
        }
      }
  
      function handleStartTag (match) {
        var tagName = match.tagName;
        var unarySlash = match.unarySlash;
  
        if (expectHTML) {
          if (lastTag === 'p' && isNonPhrasingTag(tagName)) {
            parseEndTag(lastTag);
          }
          if (canBeLeftOpenTag(tagName) && lastTag === tagName) {
            parseEndTag(tagName);
          }
        }
  
        var unary = isUnaryTag(tagName) || !!unarySlash;
  
        var l = match.attrs.length;
        var attrs = new Array(l);
        for (var i = 0; i < l; i++) {
          var args = match.attrs[i];
          var value = args[3] || args[4] || args[5] || '';
          var shouldDecodeNewlines = tagName === 'a' && args[1] === 'href'
            ? options.shouldDecodeNewlinesForHref
            : options.shouldDecodeNewlines;
          attrs[i] = {
            name: args[1],
            value: decodeAttr(value, shouldDecodeNewlines)
          };
          if ( options.outputSourceRange) {
            attrs[i].start = args.start + args[0].match(/^\s*/).length;
            attrs[i].end = args.end;
          }
        }
  
        if (!unary) {
          stack.push({ tag: tagName, lowerCasedTag: tagName.toLowerCase(), attrs: attrs, start: match.start, end: match.end });
          lastTag = tagName;
        }
  
        if (options.start) {
          options.start(tagName, attrs, unary, match.start, match.end);
        }
      }
  
      function parseEndTag (tagName, start, end) {
        var pos, lowerCasedTagName;
        if (start == null) { start = index; }
        if (end == null) { end = index; }
  
        // Find the closest opened tag of the same type
        if (tagName) {
          lowerCasedTagName = tagName.toLowerCase();
          for (pos = stack.length - 1; pos >= 0; pos--) {
            if (stack[pos].lowerCasedTag === lowerCasedTagName) {
              break
            }
          }
        } else {
          // If no tag name is provided, clean shop
          pos = 0;
        }
  
        if (pos >= 0) {
          // Close all the open elements, up the stack
          for (var i = stack.length - 1; i >= pos; i--) {
            if (
              (i > pos || !tagName) &&
              options.warn
            ) {
              options.warn(
                ("tag <" + (stack[i].tag) + "> has no matching end tag."),
                { start: stack[i].start, end: stack[i].end }
              );
            }
            if (options.end) {
              options.end(stack[i].tag, start, end);
            }
          }
  
          // Remove the open elements from the stack
          stack.length = pos;
          lastTag = pos && stack[pos - 1].tag;
        } else if (lowerCasedTagName === 'br') {
          if (options.start) {
            options.start(tagName, [], true, start, end);
          }
        } else if (lowerCasedTagName === 'p') {
          if (options.start) {
            options.start(tagName, [], false, start, end);
          }
          if (options.end) {
            options.end(tagName, start, end);
          }
        }
      }
    }
  
    /*  */
  
    var onRE = /^@|^v-on:/;
    var dirRE =  /^v-|^@|^:|^#/;
    var forAliasRE = /([\s\S]*?)\s+(?:in|of)\s+([\s\S]*)/;
    var forIteratorRE = /,([^,\}\]]*)(?:,([^,\}\]]*))?$/;
    var stripParensRE = /^\(|\)$/g;
    var dynamicArgRE = /^\[.*\]$/;
  
    var argRE = /:(.*)$/;
    var bindRE = /^:|^\.|^v-bind:/;
    var modifierRE = /\.[^.\]]+(?=[^\]]*$)/g;
  
    var slotRE = /^v-slot(:|$)|^#/;
  
    var lineBreakRE = /[\r\n]/;
    var whitespaceRE$1 = /\s+/g;
  
    var invalidAttributeRE = /[\s"'<>\/=]/;
  
    var decodeHTMLCached = cached(he.decode);
  
    var emptySlotScopeToken = "_empty_";
  
    // configurable state
    var warn$2;
    var delimiters;
    var transforms;
    var preTransforms;
    var postTransforms;
    var platformIsPreTag;
    var platformMustUseProp;
    var platformGetTagNamespace;
    var maybeComponent;
  
    function createASTElement (
      tag,
      attrs,
      parent
    ) {
      return {
        type: 1,
        tag: tag,
        attrsList: attrs,
        attrsMap: makeAttrsMap(attrs),
        rawAttrsMap: {},
        parent: parent,
        children: []
      }
    }
  
    /**
     * Convert HTML string to AST.
     */
    function parse (
      template,
      options
    ) {
      warn$2 = options.warn || baseWarn;
  
      platformIsPreTag = options.isPreTag || no;
      platformMustUseProp = options.mustUseProp || no;
      platformGetTagNamespace = options.getTagNamespace || no;
      var isReservedTag = options.isReservedTag || no;
      maybeComponent = function (el) { return !!el.component || !isReservedTag(el.tag); };
  
      transforms = pluckModuleFunction(options.modules, 'transformNode');
      preTransforms = pluckModuleFunction(options.modules, 'preTransformNode');
      postTransforms = pluckModuleFunction(options.modules, 'postTransformNode');
  
      delimiters = options.delimiters;
  
      var stack = [];
      var preserveWhitespace = options.preserveWhitespace !== false;
      var whitespaceOption = options.whitespace;
      var root;
      var currentParent;
      var inVPre = false;
      var inPre = false;
      var warned = false;
  
      function warnOnce (msg, range) {
        if (!warned) {
          warned = true;
          warn$2(msg, range);
        }
      }
  
      function closeElement (element) {
        trimEndingWhitespace(element);
        if (!inVPre && !element.processed) {
          element = processElement(element, options);
        }
        // tree management
        if (!stack.length && element !== root) {
          // allow root elements with v-if, v-else-if and v-else
          if (root.if && (element.elseif || element.else)) {
            {
              checkRootConstraints(element);
            }
            addIfCondition(root, {
              exp: element.elseif,
              block: element
            });
          } else {
            warnOnce(
              "Component template should contain exactly one root element. " +
              "If you are using v-if on multiple elements, " +
              "use v-else-if to chain them instead.",
              { start: element.start }
            );
          }
        }
        if (currentParent && !element.forbidden) {
          if (element.elseif || element.else) {
            processIfConditions(element, currentParent);
          } else {
            if (element.slotScope) {
              // scoped slot
              // keep it in the children list so that v-else(-if) conditions can
              // find it as the prev node.
              var name = element.slotTarget || '"default"'
              ;(currentParent.scopedSlots || (currentParent.scopedSlots = {}))[name] = element;
            }
            currentParent.children.push(element);
            element.parent = currentParent;
          }
        }
  
        // final children cleanup
        // filter out scoped slots
        element.children = element.children.filter(function (c) { return !(c).slotScope; });
        // remove trailing whitespace node again
        trimEndingWhitespace(element);
  
        // check pre state
        if (element.pre) {
          inVPre = false;
        }
        if (platformIsPreTag(element.tag)) {
          inPre = false;
        }
        // apply post-transforms
        for (var i = 0; i < postTransforms.length; i++) {
          postTransforms[i](element, options);
        }
      }
  
      function trimEndingWhitespace (el) {
        // remove trailing whitespace node
        if (!inPre) {
          var lastNode;
          while (
            (lastNode = el.children[el.children.length - 1]) &&
            lastNode.type === 3 &&
            lastNode.text === ' '
          ) {
            el.children.pop();
          }
        }
      }
  
      function checkRootConstraints (el) {
        if (el.tag === 'slot' || el.tag === 'template') {
          warnOnce(
            "Cannot use <" + (el.tag) + "> as component root element because it may " +
            'contain multiple nodes.',
            { start: el.start }
          );
        }
        if (el.attrsMap.hasOwnProperty('v-for')) {
          warnOnce(
            'Cannot use v-for on stateful component root element because ' +
            'it renders multiple elements.',
            el.rawAttrsMap['v-for']
          );
        }
      }
  
      parseHTML(template, {
        warn: warn$2,
        expectHTML: options.expectHTML,
        isUnaryTag: options.isUnaryTag,
        canBeLeftOpenTag: options.canBeLeftOpenTag,
        shouldDecodeNewlines: options.shouldDecodeNewlines,
        shouldDecodeNewlinesForHref: options.shouldDecodeNewlinesForHref,
        shouldKeepComment: options.comments,
        outputSourceRange: options.outputSourceRange,
        start: function start (tag, attrs, unary, start$1, end) {
          // check namespace.
          // inherit parent ns if there is one
          var ns = (currentParent && currentParent.ns) || platformGetTagNamespace(tag);
  
          // handle IE svg bug
          /* istanbul ignore if */
          if (isIE && ns === 'svg') {
            attrs = guardIESVGBug(attrs);
          }
  
          var element = createASTElement(tag, attrs, currentParent);
          if (ns) {
            element.ns = ns;
          }
  
          {
            if (options.outputSourceRange) {
              element.start = start$1;
              element.end = end;
              element.rawAttrsMap = element.attrsList.reduce(function (cumulated, attr) {
                cumulated[attr.name] = attr;
                return cumulated
              }, {});
            }
            attrs.forEach(function (attr) {
              if (invalidAttributeRE.test(attr.name)) {
                warn$2(
                  "Invalid dynamic argument expression: attribute names cannot contain " +
                  "spaces, quotes, <, >, / or =.",
                  {
                    start: attr.start + attr.name.indexOf("["),
                    end: attr.start + attr.name.length
                  }
                );
              }
            });
          }
  
          if (isForbiddenTag(element) && !isServerRendering()) {
            element.forbidden = true;
             warn$2(
              'Templates should only be responsible for mapping the state to the ' +
              'UI. Avoid placing tags with side-effects in your templates, such as ' +
              "<" + tag + ">" + ', as they will not be parsed.',
              { start: element.start }
            );
          }
  
          // apply pre-transforms
          for (var i = 0; i < preTransforms.length; i++) {
            element = preTransforms[i](element, options) || element;
          }
  
          if (!inVPre) {
            processPre(element);
            if (element.pre) {
              inVPre = true;
            }
          }
          if (platformIsPreTag(element.tag)) {
            inPre = true;
          }
          if (inVPre) {
            processRawAttrs(element);
          } else if (!element.processed) {
            // structural directives
            processFor(element);
            processIf(element);
            processOnce(element);
          }
  
          if (!root) {
            root = element;
            {
              checkRootConstraints(root);
            }
          }
  
          if (!unary) {
            currentParent = element;
            stack.push(element);
          } else {
            closeElement(element);
          }
        },
  
        end: function end (tag, start, end$1) {
          var element = stack[stack.length - 1];
          // pop stack
          stack.length -= 1;
          currentParent = stack[stack.length - 1];
          if ( options.outputSourceRange) {
            element.end = end$1;
          }
          closeElement(element);
        },
  
        chars: function chars (text, start, end) {
          if (!currentParent) {
            {
              if (text === template) {
                warnOnce(
                  'Component template requires a root element, rather than just text.',
                  { start: start }
                );
              } else if ((text = text.trim())) {
                warnOnce(
                  ("text \"" + text + "\" outside root element will be ignored."),
                  { start: start }
                );
              }
            }
            return
          }
          // IE textarea placeholder bug
          /* istanbul ignore if */
          if (isIE &&
            currentParent.tag === 'textarea' &&
            currentParent.attrsMap.placeholder === text
          ) {
            return
          }
          var children = currentParent.children;
          if (inPre || text.trim()) {
            text = isTextTag(currentParent) ? text : decodeHTMLCached(text);
          } else if (!children.length) {
            // remove the whitespace-only node right after an opening tag
            text = '';
          } else if (whitespaceOption) {
            if (whitespaceOption === 'condense') {
              // in condense mode, remove the whitespace node if it contains
              // line break, otherwise condense to a single space
              text = lineBreakRE.test(text) ? '' : ' ';
            } else {
              text = ' ';
            }
          } else {
            text = preserveWhitespace ? ' ' : '';
          }
          if (text) {
            if (!inPre && whitespaceOption === 'condense') {
              // condense consecutive whitespaces into single space
              text = text.replace(whitespaceRE$1, ' ');
            }
            var res;
            var child;
            if (!inVPre && text !== ' ' && (res = parseText(text, delimiters))) {
              child = {
                type: 2,
                expression: res.expression,
                tokens: res.tokens,
                text: text
              };
            } else if (text !== ' ' || !children.length || children[children.length - 1].text !== ' ') {
              child = {
                type: 3,
                text: text
              };
            }
            if (child) {
              if ( options.outputSourceRange) {
                child.start = start;
                child.end = end;
              }
              children.push(child);
            }
          }
        },
        comment: function comment (text, start, end) {
          // adding anything as a sibling to the root node is forbidden
          // comments should still be allowed, but ignored
          if (currentParent) {
            var child = {
              type: 3,
              text: text,
              isComment: true
            };
            if ( options.outputSourceRange) {
              child.start = start;
              child.end = end;
            }
            currentParent.children.push(child);
          }
        }
      });
      return root
    }
  
    function processPre (el) {
      if (getAndRemoveAttr(el, 'v-pre') != null) {
        el.pre = true;
      }
    }
  
    function processRawAttrs (el) {
      var list = el.attrsList;
      var len = list.length;
      if (len) {
        var attrs = el.attrs = new Array(len);
        for (var i = 0; i < len; i++) {
          attrs[i] = {
            name: list[i].name,
            value: JSON.stringify(list[i].value)
          };
          if (list[i].start != null) {
            attrs[i].start = list[i].start;
            attrs[i].end = list[i].end;
          }
        }
      } else if (!el.pre) {
        // non root node in pre blocks with no attributes
        el.plain = true;
      }
    }
  
    function processElement (
      element,
      options
    ) {
      processKey(element);
  
      // determine whether this is a plain element after
      // removing structural attributes
      element.plain = (
        !element.key &&
        !element.scopedSlots &&
        !element.attrsList.length
      );
  
      processRef(element);
      processSlotContent(element);
      processSlotOutlet(element);
      processComponent(element);
      for (var i = 0; i < transforms.length; i++) {
        element = transforms[i](element, options) || element;
      }
      processAttrs(element);
      return element
    }
  
    function processKey (el) {
      var exp = getBindingAttr(el, 'key');
      if (exp) {
        {
          if (el.tag === 'template') {
            warn$2(
              "<template> cannot be keyed. Place the key on real elements instead.",
              getRawBindingAttr(el, 'key')
            );
          }
          if (el.for) {
            var iterator = el.iterator2 || el.iterator1;
            var parent = el.parent;
            if (iterator && iterator === exp && parent && parent.tag === 'transition-group') {
              warn$2(
                "Do not use v-for index as key on <transition-group> children, " +
                "this is the same as not using keys.",
                getRawBindingAttr(el, 'key'),
                true /* tip */
              );
            }
          }
        }
        el.key = exp;
      }
    }
  
    function processRef (el) {
      var ref = getBindingAttr(el, 'ref');
      if (ref) {
        el.ref = ref;
        el.refInFor = checkInFor(el);
      }
    }
  
    function processFor (el) {
      var exp;
      if ((exp = getAndRemoveAttr(el, 'v-for'))) {
        var res = parseFor(exp);
        if (res) {
          extend(el, res);
        } else {
          warn$2(
            ("Invalid v-for expression: " + exp),
            el.rawAttrsMap['v-for']
          );
        }
      }
    }
  
  
  
    function parseFor (exp) {
      var inMatch = exp.match(forAliasRE);
      if (!inMatch) { return }
      var res = {};
      res.for = inMatch[2].trim();
      var alias = inMatch[1].trim().replace(stripParensRE, '');
      var iteratorMatch = alias.match(forIteratorRE);
      if (iteratorMatch) {
        res.alias = alias.replace(forIteratorRE, '').trim();
        res.iterator1 = iteratorMatch[1].trim();
        if (iteratorMatch[2]) {
          res.iterator2 = iteratorMatch[2].trim();
        }
      } else {
        res.alias = alias;
      }
      return res
    }
  
    function processIf (el) {
      var exp = getAndRemoveAttr(el, 'v-if');
      if (exp) {
        el.if = exp;
        addIfCondition(el, {
          exp: exp,
          block: el
        });
      } else {
        if (getAndRemoveAttr(el, 'v-else') != null) {
          el.else = true;
        }
        var elseif = getAndRemoveAttr(el, 'v-else-if');
        if (elseif) {
          el.elseif = elseif;
        }
      }
    }
  
    function processIfConditions (el, parent) {
      var prev = findPrevElement(parent.children);
      if (prev && prev.if) {
        addIfCondition(prev, {
          exp: el.elseif,
          block: el
        });
      } else {
        warn$2(
          "v-" + (el.elseif ? ('else-if="' + el.elseif + '"') : 'else') + " " +
          "used on element <" + (el.tag) + "> without corresponding v-if.",
          el.rawAttrsMap[el.elseif ? 'v-else-if' : 'v-else']
        );
      }
    }
  
    function findPrevElement (children) {
      var i = children.length;
      while (i--) {
        if (children[i].type === 1) {
          return children[i]
        } else {
          if ( children[i].text !== ' ') {
            warn$2(
              "text \"" + (children[i].text.trim()) + "\" between v-if and v-else(-if) " +
              "will be ignored.",
              children[i]
            );
          }
          children.pop();
        }
      }
    }
  
    function addIfCondition (el, condition) {
      if (!el.ifConditions) {
        el.ifConditions = [];
      }
      el.ifConditions.push(condition);
    }
  
    function processOnce (el) {
      var once = getAndRemoveAttr(el, 'v-once');
      if (once != null) {
        el.once = true;
      }
    }
  
    // handle content being passed to a component as slot,
    // e.g. <template slot="xxx">, <div slot-scope="xxx">
    function processSlotContent (el) {
      var slotScope;
      if (el.tag === 'template') {
        slotScope = getAndRemoveAttr(el, 'scope');
        /* istanbul ignore if */
        if ( slotScope) {
          warn$2(
            "the \"scope\" attribute for scoped slots have been deprecated and " +
            "replaced by \"slot-scope\" since 2.5. The new \"slot-scope\" attribute " +
            "can also be used on plain elements in addition to <template> to " +
            "denote scoped slots.",
            el.rawAttrsMap['scope'],
            true
          );
        }
        el.slotScope = slotScope || getAndRemoveAttr(el, 'slot-scope');
      } else if ((slotScope = getAndRemoveAttr(el, 'slot-scope'))) {
        /* istanbul ignore if */
        if ( el.attrsMap['v-for']) {
          warn$2(
            "Ambiguous combined usage of slot-scope and v-for on <" + (el.tag) + "> " +
            "(v-for takes higher priority). Use a wrapper <template> for the " +
            "scoped slot to make it clearer.",
            el.rawAttrsMap['slot-scope'],
            true
          );
        }
        el.slotScope = slotScope;
      }
  
      // slot="xxx"
      var slotTarget = getBindingAttr(el, 'slot');
      if (slotTarget) {
        el.slotTarget = slotTarget === '""' ? '"default"' : slotTarget;
        el.slotTargetDynamic = !!(el.attrsMap[':slot'] || el.attrsMap['v-bind:slot']);
        // preserve slot as an attribute for native shadow DOM compat
        // only for non-scoped slots.
        if (el.tag !== 'template' && !el.slotScope) {
          addAttr(el, 'slot', slotTarget, getRawBindingAttr(el, 'slot'));
        }
      }
  
      // 2.6 v-slot syntax
      {
        if (el.tag === 'template') {
          // v-slot on <template>
          var slotBinding = getAndRemoveAttrByRegex(el, slotRE);
          if (slotBinding) {
            {
              if (el.slotTarget || el.slotScope) {
                warn$2(
                  "Unexpected mixed usage of different slot syntaxes.",
                  el
                );
              }
              if (el.parent && !maybeComponent(el.parent)) {
                warn$2(
                  "<template v-slot> can only appear at the root level inside " +
                  "the receiving component",
                  el
                );
              }
            }
            var ref = getSlotName(slotBinding);
            var name = ref.name;
            var dynamic = ref.dynamic;
            el.slotTarget = name;
            el.slotTargetDynamic = dynamic;
            el.slotScope = slotBinding.value || emptySlotScopeToken; // force it into a scoped slot for perf
          }
        } else {
          // v-slot on component, denotes default slot
          var slotBinding$1 = getAndRemoveAttrByRegex(el, slotRE);
          if (slotBinding$1) {
            {
              if (!maybeComponent(el)) {
                warn$2(
                  "v-slot can only be used on components or <template>.",
                  slotBinding$1
                );
              }
              if (el.slotScope || el.slotTarget) {
                warn$2(
                  "Unexpected mixed usage of different slot syntaxes.",
                  el
                );
              }
              if (el.scopedSlots) {
                warn$2(
                  "To avoid scope ambiguity, the default slot should also use " +
                  "<template> syntax when there are other named slots.",
                  slotBinding$1
                );
              }
            }
            // add the component's children to its default slot
            var slots = el.scopedSlots || (el.scopedSlots = {});
            var ref$1 = getSlotName(slotBinding$1);
            var name$1 = ref$1.name;
            var dynamic$1 = ref$1.dynamic;
            var slotContainer = slots[name$1] = createASTElement('template', [], el);
            slotContainer.slotTarget = name$1;
            slotContainer.slotTargetDynamic = dynamic$1;
            slotContainer.children = el.children.filter(function (c) {
              if (!c.slotScope) {
                c.parent = slotContainer;
                return true
              }
            });
            slotContainer.slotScope = slotBinding$1.value || emptySlotScopeToken;
            // remove children as they are returned from scopedSlots now
            el.children = [];
            // mark el non-plain so data gets generated
            el.plain = false;
          }
        }
      }
    }
  
    function getSlotName (binding) {
      var name = binding.name.replace(slotRE, '');
      if (!name) {
        if (binding.name[0] !== '#') {
          name = 'default';
        } else {
          warn$2(
            "v-slot shorthand syntax requires a slot name.",
            binding
          );
        }
      }
      return dynamicArgRE.test(name)
        // dynamic [name]
        ? { name: name.slice(1, -1), dynamic: true }
        // static name
        : { name: ("\"" + name + "\""), dynamic: false }
    }
  
    // handle <slot/> outlets
    function processSlotOutlet (el) {
      if (el.tag === 'slot') {
        el.slotName = getBindingAttr(el, 'name');
        if ( el.key) {
          warn$2(
            "`key` does not work on <slot> because slots are abstract outlets " +
            "and can possibly expand into multiple elements. " +
            "Use the key on a wrapping element instead.",
            getRawBindingAttr(el, 'key')
          );
        }
      }
    }
  
    function processComponent (el) {
      var binding;
      if ((binding = getBindingAttr(el, 'is'))) {
        el.component = binding;
      }
      if (getAndRemoveAttr(el, 'inline-template') != null) {
        el.inlineTemplate = true;
      }
    }
  
    function processAttrs (el) {
      var list = el.attrsList;
      var i, l, name, rawName, value, modifiers, syncGen, isDynamic;
      for (i = 0, l = list.length; i < l; i++) {
        name = rawName = list[i].name;
        value = list[i].value;
        if (dirRE.test(name)) {
          // mark element as dynamic
          el.hasBindings = true;
          // modifiers
          modifiers = parseModifiers(name.replace(dirRE, ''));
          // support .foo shorthand syntax for the .prop modifier
          if (modifiers) {
            name = name.replace(modifierRE, '');
          }
          if (bindRE.test(name)) { // v-bind
            name = name.replace(bindRE, '');
            value = parseFilters(value);
            isDynamic = dynamicArgRE.test(name);
            if (isDynamic) {
              name = name.slice(1, -1);
            }
            if (
              
              value.trim().length === 0
            ) {
              warn$2(
                ("The value for a v-bind expression cannot be empty. Found in \"v-bind:" + name + "\"")
              );
            }
            if (modifiers) {
              if (modifiers.prop && !isDynamic) {
                name = camelize(name);
                if (name === 'innerHtml') { name = 'innerHTML'; }
              }
              if (modifiers.camel && !isDynamic) {
                name = camelize(name);
              }
              if (modifiers.sync) {
                syncGen = genAssignmentCode(value, "$event");
                if (!isDynamic) {
                  addHandler(
                    el,
                    ("update:" + (camelize(name))),
                    syncGen,
                    null,
                    false,
                    warn$2,
                    list[i]
                  );
                  if (hyphenate(name) !== camelize(name)) {
                    addHandler(
                      el,
                      ("update:" + (hyphenate(name))),
                      syncGen,
                      null,
                      false,
                      warn$2,
                      list[i]
                    );
                  }
                } else {
                  // handler w/ dynamic event name
                  addHandler(
                    el,
                    ("\"update:\"+(" + name + ")"),
                    syncGen,
                    null,
                    false,
                    warn$2,
                    list[i],
                    true // dynamic
                  );
                }
              }
            }
            if ((modifiers && modifiers.prop) || (
              !el.component && platformMustUseProp(el.tag, el.attrsMap.type, name)
            )) {
              addProp(el, name, value, list[i], isDynamic);
            } else {
              addAttr(el, name, value, list[i], isDynamic);
            }
          } else if (onRE.test(name)) { // v-on
            name = name.replace(onRE, '');
            isDynamic = dynamicArgRE.test(name);
            if (isDynamic) {
              name = name.slice(1, -1);
            }
            addHandler(el, name, value, modifiers, false, warn$2, list[i], isDynamic);
          } else { // normal directives
            name = name.replace(dirRE, '');
            // parse arg
            var argMatch = name.match(argRE);
            var arg = argMatch && argMatch[1];
            isDynamic = false;
            if (arg) {
              name = name.slice(0, -(arg.length + 1));
              if (dynamicArgRE.test(arg)) {
                arg = arg.slice(1, -1);
                isDynamic = true;
              }
            }
            addDirective(el, name, rawName, value, arg, isDynamic, modifiers, list[i]);
            if ( name === 'model') {
              checkForAliasModel(el, value);
            }
          }
        } else {
          // literal attribute
          {
            var res = parseText(value, delimiters);
            if (res) {
              warn$2(
                name + "=\"" + value + "\": " +
                'Interpolation inside attributes has been removed. ' +
                'Use v-bind or the colon shorthand instead. For example, ' +
                'instead of <div id="{{ val }}">, use <div :id="val">.',
                list[i]
              );
            }
          }
          addAttr(el, name, JSON.stringify(value), list[i]);
          // #6887 firefox doesn't update muted state if set via attribute
          // even immediately after element creation
          if (!el.component &&
              name === 'muted' &&
              platformMustUseProp(el.tag, el.attrsMap.type, name)) {
            addProp(el, name, 'true', list[i]);
          }
        }
      }
    }
  
    function checkInFor (el) {
      var parent = el;
      while (parent) {
        if (parent.for !== undefined) {
          return true
        }
        parent = parent.parent;
      }
      return false
    }
  
    function parseModifiers (name) {
      var match = name.match(modifierRE);
      if (match) {
        var ret = {};
        match.forEach(function (m) { ret[m.slice(1)] = true; });
        return ret
      }
    }
  
    function makeAttrsMap (attrs) {
      var map = {};
      for (var i = 0, l = attrs.length; i < l; i++) {
        if (
          
          map[attrs[i].name] && !isIE && !isEdge
        ) {
          warn$2('duplicate attribute: ' + attrs[i].name, attrs[i]);
        }
        map[attrs[i].name] = attrs[i].value;
      }
      return map
    }
  
    // for script (e.g. type="x/template") or style, do not decode content
    function isTextTag (el) {
      return el.tag === 'script' || el.tag === 'style'
    }
  
    function isForbiddenTag (el) {
      return (
        el.tag === 'style' ||
        (el.tag === 'script' && (
          !el.attrsMap.type ||
          el.attrsMap.type === 'text/javascript'
        ))
      )
    }
  
    var ieNSBug = /^xmlns:NS\d+/;
    var ieNSPrefix = /^NS\d+:/;
  
    /* istanbul ignore next */
    function guardIESVGBug (attrs) {
      var res = [];
      for (var i = 0; i < attrs.length; i++) {
        var attr = attrs[i];
        if (!ieNSBug.test(attr.name)) {
          attr.name = attr.name.replace(ieNSPrefix, '');
          res.push(attr);
        }
      }
      return res
    }
  
    function checkForAliasModel (el, value) {
      var _el = el;
      while (_el) {
        if (_el.for && _el.alias === value) {
          warn$2(
            "<" + (el.tag) + " v-model=\"" + value + "\">: " +
            "You are binding v-model directly to a v-for iteration alias. " +
            "This will not be able to modify the v-for source array because " +
            "writing to the alias is like modifying a function local variable. " +
            "Consider using an array of objects and use v-model on an object property instead.",
            el.rawAttrsMap['v-model']
          );
        }
        _el = _el.parent;
      }
    }
  
    /*  */
  
    function preTransformNode (el, options) {
      if (el.tag === 'input') {
        var map = el.attrsMap;
        if (!map['v-model']) {
          return
        }
  
        var typeBinding;
        if (map[':type'] || map['v-bind:type']) {
          typeBinding = getBindingAttr(el, 'type');
        }
        if (!map.type && !typeBinding && map['v-bind']) {
          typeBinding = "(" + (map['v-bind']) + ").type";
        }
  
        if (typeBinding) {
          var ifCondition = getAndRemoveAttr(el, 'v-if', true);
          var ifConditionExtra = ifCondition ? ("&&(" + ifCondition + ")") : "";
          var hasElse = getAndRemoveAttr(el, 'v-else', true) != null;
          var elseIfCondition = getAndRemoveAttr(el, 'v-else-if', true);
          // 1. checkbox
          var branch0 = cloneASTElement(el);
          // process for on the main node
          processFor(branch0);
          addRawAttr(branch0, 'type', 'checkbox');
          processElement(branch0, options);
          branch0.processed = true; // prevent it from double-processed
          branch0.if = "(" + typeBinding + ")==='checkbox'" + ifConditionExtra;
          addIfCondition(branch0, {
            exp: branch0.if,
            block: branch0
          });
          // 2. add radio else-if condition
          var branch1 = cloneASTElement(el);
          getAndRemoveAttr(branch1, 'v-for', true);
          addRawAttr(branch1, 'type', 'radio');
          processElement(branch1, options);
          addIfCondition(branch0, {
            exp: "(" + typeBinding + ")==='radio'" + ifConditionExtra,
            block: branch1
          });
          // 3. other
          var branch2 = cloneASTElement(el);
          getAndRemoveAttr(branch2, 'v-for', true);
          addRawAttr(branch2, ':type', typeBinding);
          processElement(branch2, options);
          addIfCondition(branch0, {
            exp: ifCondition,
            block: branch2
          });
  
          if (hasElse) {
            branch0.else = true;
          } else if (elseIfCondition) {
            branch0.elseif = elseIfCondition;
          }
  
          return branch0
        }
      }
    }
  
    function cloneASTElement (el) {
      return createASTElement(el.tag, el.attrsList.slice(), el.parent)
    }
  
    var model$1 = {
      preTransformNode: preTransformNode
    };
  
    var modules$1 = [
      klass$1,
      style$1,
      model$1
    ];
  
    /*  */
  
    function text (el, dir) {
      if (dir.value) {
        addProp(el, 'textContent', ("_s(" + (dir.value) + ")"), dir);
      }
    }
  
    /*  */
  
    function html (el, dir) {
      if (dir.value) {
        addProp(el, 'innerHTML', ("_s(" + (dir.value) + ")"), dir);
      }
    }
  
    var directives$1 = {
      model: model,
      text: text,
      html: html
    };
  
    /*  */
  
    var baseOptions = {
      expectHTML: true,
      modules: modules$1,
      directives: directives$1,
      isPreTag: isPreTag,
      isUnaryTag: isUnaryTag,
      mustUseProp: mustUseProp,
      canBeLeftOpenTag: canBeLeftOpenTag,
      isReservedTag: isReservedTag,
      getTagNamespace: getTagNamespace,
      staticKeys: genStaticKeys(modules$1)
    };
  
    /*  */
  
    var isStaticKey;
    var isPlatformReservedTag;
  
    var genStaticKeysCached = cached(genStaticKeys$1);
  
    /**
     * Goal of the optimizer: walk the generated template AST tree
     * and detect sub-trees that are purely static, i.e. parts of
     * the DOM that never needs to change.
     *
     * Once we detect these sub-trees, we can:
     *
     * 1. Hoist them into constants, so that we no longer need to
     *    create fresh nodes for them on each re-render;
     * 2. Completely skip them in the patching process.
     */
    function optimize (root, options) {
      if (!root) { return }
      isStaticKey = genStaticKeysCached(options.staticKeys || '');
      isPlatformReservedTag = options.isReservedTag || no;
      // first pass: mark all non-static nodes.
      markStatic$1(root);
      // second pass: mark static roots.
      markStaticRoots(root, false);
    }
  
    function genStaticKeys$1 (keys) {
      return makeMap(
        'type,tag,attrsList,attrsMap,plain,parent,children,attrs,start,end,rawAttrsMap' +
        (keys ? ',' + keys : '')
      )
    }
  
    function markStatic$1 (node) {
      node.static = isStatic(node);
      if (node.type === 1) {
        // do not make component slot content static. this avoids
        // 1. components not able to mutate slot nodes
        // 2. static slot content fails for hot-reloading
        if (
          !isPlatformReservedTag(node.tag) &&
          node.tag !== 'slot' &&
          node.attrsMap['inline-template'] == null
        ) {
          return
        }
        for (var i = 0, l = node.children.length; i < l; i++) {
          var child = node.children[i];
          markStatic$1(child);
          if (!child.static) {
            node.static = false;
          }
        }
        if (node.ifConditions) {
          for (var i$1 = 1, l$1 = node.ifConditions.length; i$1 < l$1; i$1++) {
            var block = node.ifConditions[i$1].block;
            markStatic$1(block);
            if (!block.static) {
              node.static = false;
            }
          }
        }
      }
    }
  
    function markStaticRoots (node, isInFor) {
      if (node.type === 1) {
        if (node.static || node.once) {
          node.staticInFor = isInFor;
        }
        // For a node to qualify as a static root, it should have children that
        // are not just static text. Otherwise the cost of hoisting out will
        // outweigh the benefits and it's better off to just always render it fresh.
        if (node.static && node.children.length && !(
          node.children.length === 1 &&
          node.children[0].type === 3
        )) {
          node.staticRoot = true;
          return
        } else {
          node.staticRoot = false;
        }
        if (node.children) {
          for (var i = 0, l = node.children.length; i < l; i++) {
            markStaticRoots(node.children[i], isInFor || !!node.for);
          }
        }
        if (node.ifConditions) {
          for (var i$1 = 1, l$1 = node.ifConditions.length; i$1 < l$1; i$1++) {
            markStaticRoots(node.ifConditions[i$1].block, isInFor);
          }
        }
      }
    }
  
    function isStatic (node) {
      if (node.type === 2) { // expression
        return false
      }
      if (node.type === 3) { // text
        return true
      }
      return !!(node.pre || (
        !node.hasBindings && // no dynamic bindings
        !node.if && !node.for && // not v-if or v-for or v-else
        !isBuiltInTag(node.tag) && // not a built-in
        isPlatformReservedTag(node.tag) && // not a component
        !isDirectChildOfTemplateFor(node) &&
        Object.keys(node).every(isStaticKey)
      ))
    }
  
    function isDirectChildOfTemplateFor (node) {
      while (node.parent) {
        node = node.parent;
        if (node.tag !== 'template') {
          return false
        }
        if (node.for) {
          return true
        }
      }
      return false
    }
  
    /*  */
  
    var fnExpRE = /^([\w$_]+|\([^)]*?\))\s*=>|^function(?:\s+[\w$]+)?\s*\(/;
    var fnInvokeRE = /\([^)]*?\);*$/;
    var simplePathRE = /^[A-Za-z_$][\w$]*(?:\.[A-Za-z_$][\w$]*|\['[^']*?']|\["[^"]*?"]|\[\d+]|\[[A-Za-z_$][\w$]*])*$/;
  
    // KeyboardEvent.keyCode aliases
    var keyCodes = {
      esc: 27,
      tab: 9,
      enter: 13,
      space: 32,
      up: 38,
      left: 37,
      right: 39,
      down: 40,
      'delete': [8, 46]
    };
  
    // KeyboardEvent.key aliases
    var keyNames = {
      // #7880: IE11 and Edge use `Esc` for Escape key name.
      esc: ['Esc', 'Escape'],
      tab: 'Tab',
      enter: 'Enter',
      // #9112: IE11 uses `Spacebar` for Space key name.
      space: [' ', 'Spacebar'],
      // #7806: IE11 uses key names without `Arrow` prefix for arrow keys.
      up: ['Up', 'ArrowUp'],
      left: ['Left', 'ArrowLeft'],
      right: ['Right', 'ArrowRight'],
      down: ['Down', 'ArrowDown'],
      // #9112: IE11 uses `Del` for Delete key name.
      'delete': ['Backspace', 'Delete', 'Del']
    };
  
    // #4868: modifiers that prevent the execution of the listener
    // need to explicitly return null so that we can determine whether to remove
    // the listener for .once
    var genGuard = function (condition) { return ("if(" + condition + ")return null;"); };
  
    var modifierCode = {
      stop: '$event.stopPropagation();',
      prevent: '$event.preventDefault();',
      self: genGuard("$event.target !== $event.currentTarget"),
      ctrl: genGuard("!$event.ctrlKey"),
      shift: genGuard("!$event.shiftKey"),
      alt: genGuard("!$event.altKey"),
      meta: genGuard("!$event.metaKey"),
      left: genGuard("'button' in $event && $event.button !== 0"),
      middle: genGuard("'button' in $event && $event.button !== 1"),
      right: genGuard("'button' in $event && $event.button !== 2")
    };
  
    function genHandlers (
      events,
      isNative
    ) {
      var prefix = isNative ? 'nativeOn:' : 'on:';
      var staticHandlers = "";
      var dynamicHandlers = "";
      for (var name in events) {
        var handlerCode = genHandler(events[name]);
        if (events[name] && events[name].dynamic) {
          dynamicHandlers += name + "," + handlerCode + ",";
        } else {
          staticHandlers += "\"" + name + "\":" + handlerCode + ",";
        }
      }
      staticHandlers = "{" + (staticHandlers.slice(0, -1)) + "}";
      if (dynamicHandlers) {
        return prefix + "_d(" + staticHandlers + ",[" + (dynamicHandlers.slice(0, -1)) + "])"
      } else {
        return prefix + staticHandlers
      }
    }
  
    function genHandler (handler) {
      if (!handler) {
        return 'function(){}'
      }
  
      if (Array.isArray(handler)) {
        return ("[" + (handler.map(function (handler) { return genHandler(handler); }).join(',')) + "]")
      }
  
      var isMethodPath = simplePathRE.test(handler.value);
      var isFunctionExpression = fnExpRE.test(handler.value);
      var isFunctionInvocation = simplePathRE.test(handler.value.replace(fnInvokeRE, ''));
  
      if (!handler.modifiers) {
        if (isMethodPath || isFunctionExpression) {
          return handler.value
        }
        return ("function($event){" + (isFunctionInvocation ? ("return " + (handler.value)) : handler.value) + "}") // inline statement
      } else {
        var code = '';
        var genModifierCode = '';
        var keys = [];
        for (var key in handler.modifiers) {
          if (modifierCode[key]) {
            genModifierCode += modifierCode[key];
            // left/right
            if (keyCodes[key]) {
              keys.push(key);
            }
          } else if (key === 'exact') {
            var modifiers = (handler.modifiers);
            genModifierCode += genGuard(
              ['ctrl', 'shift', 'alt', 'meta']
                .filter(function (keyModifier) { return !modifiers[keyModifier]; })
                .map(function (keyModifier) { return ("$event." + keyModifier + "Key"); })
                .join('||')
            );
          } else {
            keys.push(key);
          }
        }
        if (keys.length) {
          code += genKeyFilter(keys);
        }
        // Make sure modifiers like prevent and stop get executed after key filtering
        if (genModifierCode) {
          code += genModifierCode;
        }
        var handlerCode = isMethodPath
          ? ("return " + (handler.value) + "($event)")
          : isFunctionExpression
            ? ("return (" + (handler.value) + ")($event)")
            : isFunctionInvocation
              ? ("return " + (handler.value))
              : handler.value;
        return ("function($event){" + code + handlerCode + "}")
      }
    }
  
    function genKeyFilter (keys) {
      return (
        // make sure the key filters only apply to KeyboardEvents
        // #9441: can't use 'keyCode' in $event because Chrome autofill fires fake
        // key events that do not have keyCode property...
        "if(!$event.type.indexOf('key')&&" +
        (keys.map(genFilterCode).join('&&')) + ")return null;"
      )
    }
  
    function genFilterCode (key) {
      var keyVal = parseInt(key, 10);
      if (keyVal) {
        return ("$event.keyCode!==" + keyVal)
      }
      var keyCode = keyCodes[key];
      var keyName = keyNames[key];
      return (
        "_k($event.keyCode," +
        (JSON.stringify(key)) + "," +
        (JSON.stringify(keyCode)) + "," +
        "$event.key," +
        "" + (JSON.stringify(keyName)) +
        ")"
      )
    }
  
    /*  */
  
    function on (el, dir) {
      if ( dir.modifiers) {
        warn("v-on without argument does not support modifiers.");
      }
      el.wrapListeners = function (code) { return ("_g(" + code + "," + (dir.value) + ")"); };
    }
  
    /*  */
  
    function bind$1 (el, dir) {
      el.wrapData = function (code) {
        return ("_b(" + code + ",'" + (el.tag) + "'," + (dir.value) + "," + (dir.modifiers && dir.modifiers.prop ? 'true' : 'false') + (dir.modifiers && dir.modifiers.sync ? ',true' : '') + ")")
      };
    }
  
    /*  */
  
    var baseDirectives = {
      on: on,
      bind: bind$1,
      cloak: noop
    };
  
    /*  */
  
  
  
  
  
    var CodegenState = function CodegenState (options) {
      this.options = options;
      this.warn = options.warn || baseWarn;
      this.transforms = pluckModuleFunction(options.modules, 'transformCode');
      this.dataGenFns = pluckModuleFunction(options.modules, 'genData');
      this.directives = extend(extend({}, baseDirectives), options.directives);
      var isReservedTag = options.isReservedTag || no;
      this.maybeComponent = function (el) { return !!el.component || !isReservedTag(el.tag); };
      this.onceId = 0;
      this.staticRenderFns = [];
      this.pre = false;
    };
  
  
  
    function generate (
      ast,
      options
    ) {
      var state = new CodegenState(options);
      var code = ast ? genElement(ast, state) : '_c("div")';
      return {
        render: ("with(this){return " + code + "}"),
        staticRenderFns: state.staticRenderFns
      }
    }
  
    function genElement (el, state) {
      if (el.parent) {
        el.pre = el.pre || el.parent.pre;
      }
  
      if (el.staticRoot && !el.staticProcessed) {
        return genStatic(el, state)
      } else if (el.once && !el.onceProcessed) {
        return genOnce(el, state)
      } else if (el.for && !el.forProcessed) {
        return genFor(el, state)
      } else if (el.if && !el.ifProcessed) {
        return genIf(el, state)
      } else if (el.tag === 'template' && !el.slotTarget && !state.pre) {
        return genChildren(el, state) || 'void 0'
      } else if (el.tag === 'slot') {
        return genSlot(el, state)
      } else {
        // component or element
        var code;
        if (el.component) {
          code = genComponent(el.component, el, state);
        } else {
          var data;
          if (!el.plain || (el.pre && state.maybeComponent(el))) {
            data = genData$2(el, state);
          }
  
          var children = el.inlineTemplate ? null : genChildren(el, state, true);
          code = "_c('" + (el.tag) + "'" + (data ? ("," + data) : '') + (children ? ("," + children) : '') + ")";
        }
        // module transforms
        for (var i = 0; i < state.transforms.length; i++) {
          code = state.transforms[i](el, code);
        }
        return code
      }
    }
  
    // hoist static sub-trees out
    function genStatic (el, state) {
      el.staticProcessed = true;
      // Some elements (templates) need to behave differently inside of a v-pre
      // node.  All pre nodes are static roots, so we can use this as a location to
      // wrap a state change and reset it upon exiting the pre node.
      var originalPreState = state.pre;
      if (el.pre) {
        state.pre = el.pre;
      }
      state.staticRenderFns.push(("with(this){return " + (genElement(el, state)) + "}"));
      state.pre = originalPreState;
      return ("_m(" + (state.staticRenderFns.length - 1) + (el.staticInFor ? ',true' : '') + ")")
    }
  
    // v-once
    function genOnce (el, state) {
      el.onceProcessed = true;
      if (el.if && !el.ifProcessed) {
        return genIf(el, state)
      } else if (el.staticInFor) {
        var key = '';
        var parent = el.parent;
        while (parent) {
          if (parent.for) {
            key = parent.key;
            break
          }
          parent = parent.parent;
        }
        if (!key) {
           state.warn(
            "v-once can only be used inside v-for that is keyed. ",
            el.rawAttrsMap['v-once']
          );
          return genElement(el, state)
        }
        return ("_o(" + (genElement(el, state)) + "," + (state.onceId++) + "," + key + ")")
      } else {
        return genStatic(el, state)
      }
    }
  
    function genIf (
      el,
      state,
      altGen,
      altEmpty
    ) {
      el.ifProcessed = true; // avoid recursion
      return genIfConditions(el.ifConditions.slice(), state, altGen, altEmpty)
    }
  
    function genIfConditions (
      conditions,
      state,
      altGen,
      altEmpty
    ) {
      if (!conditions.length) {
        return altEmpty || '_e()'
      }
  
      var condition = conditions.shift();
      if (condition.exp) {
        return ("(" + (condition.exp) + ")?" + (genTernaryExp(condition.block)) + ":" + (genIfConditions(conditions, state, altGen, altEmpty)))
      } else {
        return ("" + (genTernaryExp(condition.block)))
      }
  
      // v-if with v-once should generate code like (a)?_m(0):_m(1)
      function genTernaryExp (el) {
        return altGen
          ? altGen(el, state)
          : el.once
            ? genOnce(el, state)
            : genElement(el, state)
      }
    }
  
    function genFor (
      el,
      state,
      altGen,
      altHelper
    ) {
      var exp = el.for;
      var alias = el.alias;
      var iterator1 = el.iterator1 ? ("," + (el.iterator1)) : '';
      var iterator2 = el.iterator2 ? ("," + (el.iterator2)) : '';
  
      if (
        state.maybeComponent(el) &&
        el.tag !== 'slot' &&
        el.tag !== 'template' &&
        !el.key
      ) {
        state.warn(
          "<" + (el.tag) + " v-for=\"" + alias + " in " + exp + "\">: component lists rendered with " +
          "v-for should have explicit keys. " +
          "See https://vuejs.org/guide/list.html#key for more info.",
          el.rawAttrsMap['v-for'],
          true /* tip */
        );
      }
  
      el.forProcessed = true; // avoid recursion
      return (altHelper || '_l') + "((" + exp + ")," +
        "function(" + alias + iterator1 + iterator2 + "){" +
          "return " + ((altGen || genElement)(el, state)) +
        '})'
    }
  
    function genData$2 (el, state) {
      var data = '{';
  
      // directives first.
      // directives may mutate the el's other properties before they are generated.
      var dirs = genDirectives(el, state);
      if (dirs) { data += dirs + ','; }
  
      // key
      if (el.key) {
        data += "key:" + (el.key) + ",";
      }
      // ref
      if (el.ref) {
        data += "ref:" + (el.ref) + ",";
      }
      if (el.refInFor) {
        data += "refInFor:true,";
      }
      // pre
      if (el.pre) {
        data += "pre:true,";
      }
      // record original tag name for components using "is" attribute
      if (el.component) {
        data += "tag:\"" + (el.tag) + "\",";
      }
      // module data generation functions
      for (var i = 0; i < state.dataGenFns.length; i++) {
        data += state.dataGenFns[i](el);
      }
      // attributes
      if (el.attrs) {
        data += "attrs:" + (genProps(el.attrs)) + ",";
      }
      // DOM props
      if (el.props) {
        data += "domProps:" + (genProps(el.props)) + ",";
      }
      // event handlers
      if (el.events) {
        data += (genHandlers(el.events, false)) + ",";
      }
      if (el.nativeEvents) {
        data += (genHandlers(el.nativeEvents, true)) + ",";
      }
      // slot target
      // only for non-scoped slots
      if (el.slotTarget && !el.slotScope) {
        data += "slot:" + (el.slotTarget) + ",";
      }
      // scoped slots
      if (el.scopedSlots) {
        data += (genScopedSlots(el, el.scopedSlots, state)) + ",";
      }
      // component v-model
      if (el.model) {
        data += "model:{value:" + (el.model.value) + ",callback:" + (el.model.callback) + ",expression:" + (el.model.expression) + "},";
      }
      // inline-template
      if (el.inlineTemplate) {
        var inlineTemplate = genInlineTemplate(el, state);
        if (inlineTemplate) {
          data += inlineTemplate + ",";
        }
      }
      data = data.replace(/,$/, '') + '}';
      // v-bind dynamic argument wrap
      // v-bind with dynamic arguments must be applied using the same v-bind object
      // merge helper so that class/style/mustUseProp attrs are handled correctly.
      if (el.dynamicAttrs) {
        data = "_b(" + data + ",\"" + (el.tag) + "\"," + (genProps(el.dynamicAttrs)) + ")";
      }
      // v-bind data wrap
      if (el.wrapData) {
        data = el.wrapData(data);
      }
      // v-on data wrap
      if (el.wrapListeners) {
        data = el.wrapListeners(data);
      }
      return data
    }
  
    function genDirectives (el, state) {
      var dirs = el.directives;
      if (!dirs) { return }
      var res = 'directives:[';
      var hasRuntime = false;
      var i, l, dir, needRuntime;
      for (i = 0, l = dirs.length; i < l; i++) {
        dir = dirs[i];
        needRuntime = true;
        var gen = state.directives[dir.name];
        if (gen) {
          // compile-time directive that manipulates AST.
          // returns true if it also needs a runtime counterpart.
          needRuntime = !!gen(el, dir, state.warn);
        }
        if (needRuntime) {
          hasRuntime = true;
          res += "{name:\"" + (dir.name) + "\",rawName:\"" + (dir.rawName) + "\"" + (dir.value ? (",value:(" + (dir.value) + "),expression:" + (JSON.stringify(dir.value))) : '') + (dir.arg ? (",arg:" + (dir.isDynamicArg ? dir.arg : ("\"" + (dir.arg) + "\""))) : '') + (dir.modifiers ? (",modifiers:" + (JSON.stringify(dir.modifiers))) : '') + "},";
        }
      }
      if (hasRuntime) {
        return res.slice(0, -1) + ']'
      }
    }
  
    function genInlineTemplate (el, state) {
      var ast = el.children[0];
      if ( (
        el.children.length !== 1 || ast.type !== 1
      )) {
        state.warn(
          'Inline-template components must have exactly one child element.',
          { start: el.start }
        );
      }
      if (ast && ast.type === 1) {
        var inlineRenderFns = generate(ast, state.options);
        return ("inlineTemplate:{render:function(){" + (inlineRenderFns.render) + "},staticRenderFns:[" + (inlineRenderFns.staticRenderFns.map(function (code) { return ("function(){" + code + "}"); }).join(',')) + "]}")
      }
    }
  
    function genScopedSlots (
      el,
      slots,
      state
    ) {
      // by default scoped slots are considered "stable", this allows child
      // components with only scoped slots to skip forced updates from parent.
      // but in some cases we have to bail-out of this optimization
      // for example if the slot contains dynamic names, has v-if or v-for on them...
      var needsForceUpdate = el.for || Object.keys(slots).some(function (key) {
        var slot = slots[key];
        return (
          slot.slotTargetDynamic ||
          slot.if ||
          slot.for ||
          containsSlotChild(slot) // is passing down slot from parent which may be dynamic
        )
      });
  
      // #9534: if a component with scoped slots is inside a conditional branch,
      // it's possible for the same component to be reused but with different
      // compiled slot content. To avoid that, we generate a unique key based on
      // the generated code of all the slot contents.
      var needsKey = !!el.if;
  
      // OR when it is inside another scoped slot or v-for (the reactivity may be
      // disconnected due to the intermediate scope variable)
      // #9438, #9506
      // TODO: this can be further optimized by properly analyzing in-scope bindings
      // and skip force updating ones that do not actually use scope variables.
      if (!needsForceUpdate) {
        var parent = el.parent;
        while (parent) {
          if (
            (parent.slotScope && parent.slotScope !== emptySlotScopeToken) ||
            parent.for
          ) {
            needsForceUpdate = true;
            break
          }
          if (parent.if) {
            needsKey = true;
          }
          parent = parent.parent;
        }
      }
  
      var generatedSlots = Object.keys(slots)
        .map(function (key) { return genScopedSlot(slots[key], state); })
        .join(',');
  
      return ("scopedSlots:_u([" + generatedSlots + "]" + (needsForceUpdate ? ",null,true" : "") + (!needsForceUpdate && needsKey ? (",null,false," + (hash(generatedSlots))) : "") + ")")
    }
  
    function hash(str) {
      var hash = 5381;
      var i = str.length;
      while(i) {
        hash = (hash * 33) ^ str.charCodeAt(--i);
      }
      return hash >>> 0
    }
  
    function containsSlotChild (el) {
      if (el.type === 1) {
        if (el.tag === 'slot') {
          return true
        }
        return el.children.some(containsSlotChild)
      }
      return false
    }
  
    function genScopedSlot (
      el,
      state
    ) {
      var isLegacySyntax = el.attrsMap['slot-scope'];
      if (el.if && !el.ifProcessed && !isLegacySyntax) {
        return genIf(el, state, genScopedSlot, "null")
      }
      if (el.for && !el.forProcessed) {
        return genFor(el, state, genScopedSlot)
      }
      var slotScope = el.slotScope === emptySlotScopeToken
        ? ""
        : String(el.slotScope);
      var fn = "function(" + slotScope + "){" +
        "return " + (el.tag === 'template'
          ? el.if && isLegacySyntax
            ? ("(" + (el.if) + ")?" + (genChildren(el, state) || 'undefined') + ":undefined")
            : genChildren(el, state) || 'undefined'
          : genElement(el, state)) + "}";
      // reverse proxy v-slot without scope on this.$slots
      var reverseProxy = slotScope ? "" : ",proxy:true";
      return ("{key:" + (el.slotTarget || "\"default\"") + ",fn:" + fn + reverseProxy + "}")
    }
  
    function genChildren (
      el,
      state,
      checkSkip,
      altGenElement,
      altGenNode
    ) {
      var children = el.children;
      if (children.length) {
        var el$1 = children[0];
        // optimize single v-for
        if (children.length === 1 &&
          el$1.for &&
          el$1.tag !== 'template' &&
          el$1.tag !== 'slot'
        ) {
          var normalizationType = checkSkip
            ? state.maybeComponent(el$1) ? ",1" : ",0"
            : "";
          return ("" + ((altGenElement || genElement)(el$1, state)) + normalizationType)
        }
        var normalizationType$1 = checkSkip
          ? getNormalizationType(children, state.maybeComponent)
          : 0;
        var gen = altGenNode || genNode;
        return ("[" + (children.map(function (c) { return gen(c, state); }).join(',')) + "]" + (normalizationType$1 ? ("," + normalizationType$1) : ''))
      }
    }
  
    // determine the normalization needed for the children array.
    // 0: no normalization needed
    // 1: simple normalization needed (possible 1-level deep nested array)
    // 2: full normalization needed
    function getNormalizationType (
      children,
      maybeComponent
    ) {
      var res = 0;
      for (var i = 0; i < children.length; i++) {
        var el = children[i];
        if (el.type !== 1) {
          continue
        }
        if (needsNormalization(el) ||
            (el.ifConditions && el.ifConditions.some(function (c) { return needsNormalization(c.block); }))) {
          res = 2;
          break
        }
        if (maybeComponent(el) ||
            (el.ifConditions && el.ifConditions.some(function (c) { return maybeComponent(c.block); }))) {
          res = 1;
        }
      }
      return res
    }
  
    function needsNormalization (el) {
      return el.for !== undefined || el.tag === 'template' || el.tag === 'slot'
    }
  
    function genNode (node, state) {
      if (node.type === 1) {
        return genElement(node, state)
      } else if (node.type === 3 && node.isComment) {
        return genComment(node)
      } else {
        return genText(node)
      }
    }
  
    function genText (text) {
      return ("_v(" + (text.type === 2
        ? text.expression // no need for () because already wrapped in _s()
        : transformSpecialNewlines(JSON.stringify(text.text))) + ")")
    }
  
    function genComment (comment) {
      return ("_e(" + (JSON.stringify(comment.text)) + ")")
    }
  
    function genSlot (el, state) {
      var slotName = el.slotName || '"default"';
      var children = genChildren(el, state);
      var res = "_t(" + slotName + (children ? ("," + children) : '');
      var attrs = el.attrs || el.dynamicAttrs
        ? genProps((el.attrs || []).concat(el.dynamicAttrs || []).map(function (attr) { return ({
            // slot props are camelized
            name: camelize(attr.name),
            value: attr.value,
            dynamic: attr.dynamic
          }); }))
        : null;
      var bind = el.attrsMap['v-bind'];
      if ((attrs || bind) && !children) {
        res += ",null";
      }
      if (attrs) {
        res += "," + attrs;
      }
      if (bind) {
        res += (attrs ? '' : ',null') + "," + bind;
      }
      return res + ')'
    }
  
    // componentName is el.component, take it as argument to shun flow's pessimistic refinement
    function genComponent (
      componentName,
      el,
      state
    ) {
      var children = el.inlineTemplate ? null : genChildren(el, state, true);
      return ("_c(" + componentName + "," + (genData$2(el, state)) + (children ? ("," + children) : '') + ")")
    }
  
    function genProps (props) {
      var staticProps = "";
      var dynamicProps = "";
      for (var i = 0; i < props.length; i++) {
        var prop = props[i];
        var value =  transformSpecialNewlines(prop.value);
        if (prop.dynamic) {
          dynamicProps += (prop.name) + "," + value + ",";
        } else {
          staticProps += "\"" + (prop.name) + "\":" + value + ",";
        }
      }
      staticProps = "{" + (staticProps.slice(0, -1)) + "}";
      if (dynamicProps) {
        return ("_d(" + staticProps + ",[" + (dynamicProps.slice(0, -1)) + "])")
      } else {
        return staticProps
      }
    }
  
    // #3895, #4268
    function transformSpecialNewlines (text) {
      return text
        .replace(/\u2028/g, '\\u2028')
        .replace(/\u2029/g, '\\u2029')
    }
  
    /*  */
  
  
  
    // these keywords should not appear inside expressions, but operators like
    // typeof, instanceof and in are allowed
    var prohibitedKeywordRE = new RegExp('\\b' + (
      'do,if,for,let,new,try,var,case,else,with,await,break,catch,class,const,' +
      'super,throw,while,yield,delete,export,import,return,switch,default,' +
      'extends,finally,continue,debugger,function,arguments'
    ).split(',').join('\\b|\\b') + '\\b');
  
    // these unary operators should not be used as property/method names
    var unaryOperatorsRE = new RegExp('\\b' + (
      'delete,typeof,void'
    ).split(',').join('\\s*\\([^\\)]*\\)|\\b') + '\\s*\\([^\\)]*\\)');
  
    // strip strings in expressions
    var stripStringRE = /'(?:[^'\\]|\\.)*'|"(?:[^"\\]|\\.)*"|`(?:[^`\\]|\\.)*\$\{|\}(?:[^`\\]|\\.)*`|`(?:[^`\\]|\\.)*`/g;
  
    // detect problematic expressions in a template
    function detectErrors (ast, warn) {
      if (ast) {
        checkNode(ast, warn);
      }
    }
  
    function checkNode (node, warn) {
      if (node.type === 1) {
        for (var name in node.attrsMap) {
          if (dirRE.test(name)) {
            var value = node.attrsMap[name];
            if (value) {
              var range = node.rawAttrsMap[name];
              if (name === 'v-for') {
                checkFor(node, ("v-for=\"" + value + "\""), warn, range);
              } else if (name === 'v-slot' || name[0] === '#') {
                checkFunctionParameterExpression(value, (name + "=\"" + value + "\""), warn, range);
              } else if (onRE.test(name)) {
                checkEvent(value, (name + "=\"" + value + "\""), warn, range);
              } else {
                checkExpression(value, (name + "=\"" + value + "\""), warn, range);
              }
            }
          }
        }
        if (node.children) {
          for (var i = 0; i < node.children.length; i++) {
            checkNode(node.children[i], warn);
          }
        }
      } else if (node.type === 2) {
        checkExpression(node.expression, node.text, warn, node);
      }
    }
  
    function checkEvent (exp, text, warn, range) {
      var stripped = exp.replace(stripStringRE, '');
      var keywordMatch = stripped.match(unaryOperatorsRE);
      if (keywordMatch && stripped.charAt(keywordMatch.index - 1) !== '$') {
        warn(
          "avoid using JavaScript unary operator as property name: " +
          "\"" + (keywordMatch[0]) + "\" in expression " + (text.trim()),
          range
        );
      }
      checkExpression(exp, text, warn, range);
    }
  
    function checkFor (node, text, warn, range) {
      checkExpression(node.for || '', text, warn, range);
      checkIdentifier(node.alias, 'v-for alias', text, warn, range);
      checkIdentifier(node.iterator1, 'v-for iterator', text, warn, range);
      checkIdentifier(node.iterator2, 'v-for iterator', text, warn, range);
    }
  
    function checkIdentifier (
      ident,
      type,
      text,
      warn,
      range
    ) {
      if (typeof ident === 'string') {
        try {
          new Function(("var " + ident + "=_"));
        } catch (e) {
          warn(("invalid " + type + " \"" + ident + "\" in expression: " + (text.trim())), range);
        }
      }
    }
  
    function checkExpression (exp, text, warn, range) {
      try {
        new Function(("return " + exp));
      } catch (e) {
        var keywordMatch = exp.replace(stripStringRE, '').match(prohibitedKeywordRE);
        if (keywordMatch) {
          warn(
            "avoid using JavaScript keyword as property name: " +
            "\"" + (keywordMatch[0]) + "\"\n  Raw expression: " + (text.trim()),
            range
          );
        } else {
          warn(
            "invalid expression: " + (e.message) + " in\n\n" +
            "    " + exp + "\n\n" +
            "  Raw expression: " + (text.trim()) + "\n",
            range
          );
        }
      }
    }
  
    function checkFunctionParameterExpression (exp, text, warn, range) {
      try {
        new Function(exp, '');
      } catch (e) {
        warn(
          "invalid function parameter expression: " + (e.message) + " in\n\n" +
          "    " + exp + "\n\n" +
          "  Raw expression: " + (text.trim()) + "\n",
          range
        );
      }
    }
  
    /*  */
  
    var range = 2;
  
    function generateCodeFrame (
      source,
      start,
      end
    ) {
      if ( start === void 0 ) start = 0;
      if ( end === void 0 ) end = source.length;
  
      var lines = source.split(/\r?\n/);
      var count = 0;
      var res = [];
      for (var i = 0; i < lines.length; i++) {
        count += lines[i].length + 1;
        if (count >= start) {
          for (var j = i - range; j <= i + range || end > count; j++) {
            if (j < 0 || j >= lines.length) { continue }
            res.push(("" + (j + 1) + (repeat$1(" ", 3 - String(j + 1).length)) + "|  " + (lines[j])));
            var lineLength = lines[j].length;
            if (j === i) {
              // push underline
              var pad = start - (count - lineLength) + 1;
              var length = end > count ? lineLength - pad : end - start;
              res.push("   |  " + repeat$1(" ", pad) + repeat$1("^", length));
            } else if (j > i) {
              if (end > count) {
                var length$1 = Math.min(end - count, lineLength);
                res.push("   |  " + repeat$1("^", length$1));
              }
              count += lineLength + 1;
            }
          }
          break
        }
      }
      return res.join('\n')
    }
  
    function repeat$1 (str, n) {
      var result = '';
      if (n > 0) {
        while (true) { // eslint-disable-line
          if (n & 1) { result += str; }
          n >>>= 1;
          if (n <= 0) { break }
          str += str;
        }
      }
      return result
    }
  
    /*  */
  
  
  
    function createFunction (code, errors) {
      try {
        return new Function(code)
      } catch (err) {
        errors.push({ err: err, code: code });
        return noop
      }
    }
  
    function createCompileToFunctionFn (compile) {
      var cache = Object.create(null);
  
      return function compileToFunctions (
        template,
        options,
        vm
      ) {
        options = extend({}, options);
        var warn$1 = options.warn || warn;
        delete options.warn;
  
        /* istanbul ignore if */
        {
          // detect possible CSP restriction
          try {
            new Function('return 1');
          } catch (e) {
            if (e.toString().match(/unsafe-eval|CSP/)) {
              warn$1(
                'It seems you are using the standalone build of Vue.js in an ' +
                'environment with Content Security Policy that prohibits unsafe-eval. ' +
                'The template compiler cannot work in this environment. Consider ' +
                'relaxing the policy to allow unsafe-eval or pre-compiling your ' +
                'templates into render functions.'
              );
            }
          }
        }
  
        // check cache
        var key = options.delimiters
          ? String(options.delimiters) + template
          : template;
        if (cache[key]) {
          return cache[key]
        }
  
        // compile
        var compiled = compile(template, options);
  
        // check compilation errors/tips
        {
          if (compiled.errors && compiled.errors.length) {
            if (options.outputSourceRange) {
              compiled.errors.forEach(function (e) {
                warn$1(
                  "Error compiling template:\n\n" + (e.msg) + "\n\n" +
                  generateCodeFrame(template, e.start, e.end),
                  vm
                );
              });
            } else {
              warn$1(
                "Error compiling template:\n\n" + template + "\n\n" +
                compiled.errors.map(function (e) { return ("- " + e); }).join('\n') + '\n',
                vm
              );
            }
          }
          if (compiled.tips && compiled.tips.length) {
            if (options.outputSourceRange) {
              compiled.tips.forEach(function (e) { return tip(e.msg, vm); });
            } else {
              compiled.tips.forEach(function (msg) { return tip(msg, vm); });
            }
          }
        }
  
        // turn code into functions
        var res = {};
        var fnGenErrors = [];
        res.render = createFunction(compiled.render, fnGenErrors);
        res.staticRenderFns = compiled.staticRenderFns.map(function (code) {
          return createFunction(code, fnGenErrors)
        });
  
        // check function generation errors.
        // this should only happen if there is a bug in the compiler itself.
        // mostly for codegen development use
        /* istanbul ignore if */
        {
          if ((!compiled.errors || !compiled.errors.length) && fnGenErrors.length) {
            warn$1(
              "Failed to generate render function:\n\n" +
              fnGenErrors.map(function (ref) {
                var err = ref.err;
                var code = ref.code;
  
                return ((err.toString()) + " in\n\n" + code + "\n");
            }).join('\n'),
              vm
            );
          }
        }
  
        return (cache[key] = res)
      }
    }
  
    /*  */
  
    function createCompilerCreator (baseCompile) {
      return function createCompiler (baseOptions) {
        function compile (
          template,
          options
        ) {
          var finalOptions = Object.create(baseOptions);
          var errors = [];
          var tips = [];
  
          var warn = function (msg, range, tip) {
            (tip ? tips : errors).push(msg);
          };
  
          if (options) {
            if ( options.outputSourceRange) {
              // $flow-disable-line
              var leadingSpaceLength = template.match(/^\s*/)[0].length;
  
              warn = function (msg, range, tip) {
                var data = { msg: msg };
                if (range) {
                  if (range.start != null) {
                    data.start = range.start + leadingSpaceLength;
                  }
                  if (range.end != null) {
                    data.end = range.end + leadingSpaceLength;
                  }
                }
                (tip ? tips : errors).push(data);
              };
            }
            // merge custom modules
            if (options.modules) {
              finalOptions.modules =
                (baseOptions.modules || []).concat(options.modules);
            }
            // merge custom directives
            if (options.directives) {
              finalOptions.directives = extend(
                Object.create(baseOptions.directives || null),
                options.directives
              );
            }
            // copy other options
            for (var key in options) {
              if (key !== 'modules' && key !== 'directives') {
                finalOptions[key] = options[key];
              }
            }
          }
  
          finalOptions.warn = warn;
  
          var compiled = baseCompile(template.trim(), finalOptions);
          {
            detectErrors(compiled.ast, warn);
          }
          compiled.errors = errors;
          compiled.tips = tips;
          return compiled
        }
  
        return {
          compile: compile,
          compileToFunctions: createCompileToFunctionFn(compile)
        }
      }
    }
  
    /*  */
  
    // `createCompilerCreator` allows creating compilers that use alternative
    // parser/optimizer/codegen, e.g the SSR optimizing compiler.
    // Here we just export a default compiler using the default parts.
    var createCompiler = createCompilerCreator(function baseCompile (
      template,
      options
    ) {
      var ast = parse(template.trim(), options);
      if (options.optimize !== false) {
        optimize(ast, options);
      }
      var code = generate(ast, options);
      return {
        ast: ast,
        render: code.render,
        staticRenderFns: code.staticRenderFns
      }
    });
  
    /*  */
  
    var ref$1 = createCompiler(baseOptions);
    var compileToFunctions = ref$1.compileToFunctions;
  
    /*  */
  
    // check whether current browser encodes a char inside attribute values
    var div;
    function getShouldDecode (href) {
      div = div || document.createElement('div');
      div.innerHTML = href ? "<a href=\"\n\"/>" : "<div a=\"\n\"/>";
      return div.innerHTML.indexOf('&#10;') > 0
    }
  
    // #3663: IE encodes newlines inside attribute values while other browsers don't
    var shouldDecodeNewlines = inBrowser ? getShouldDecode(false) : false;
    // #6828: chrome encodes content in a[href]
    var shouldDecodeNewlinesForHref = inBrowser ? getShouldDecode(true) : false;
  
    /*  */
  
    var idToTemplate = cached(function (id) {
      var el = query(id);
      return el && el.innerHTML
    });
    // web平台拓展$mount
    var mount = Vue.prototype.$mount;
    Vue.prototype.$mount = function (
      el,
      hydrating
    ) {
      // 获取dom元素
      el = el && query(el);
  
      /* istanbul ignore if */
      if (el === document.body || el === document.documentElement) {
         warn(
          "Do not mount Vue to <html> or <body> - mount to normal elements instead."
        );
        return this
      }
  
      var options = this.$options;
      // resolve template/el and convert to render function 
      // el < template < render 优先级
      // render优先级最高
      if (!options.render) {
        // 没有render找template
        var template = options.template;
        if (template) {
          if (typeof template === 'string') {
            if (template.charAt(0) === '#') {
              template = idToTemplate(template);
              /* istanbul ignore if */
              if ( !template) {
                warn(
                  ("Template element not found or is empty: " + (options.template)),
                  this
                );
              }
            }
          } else if (template.nodeType) {
            template = template.innerHTML;
          } else {
            {
              warn('invalid template option:' + template, this);
            }
            return this
          }
        } else if (el) {
          // 最后才是el元素内部的内容作为模板
          template = getOuterHTML(el);
        }
        if (template) {
          /* istanbul ignore if */
          if ( config.performance && mark) {
            mark('compile');
          }
          // 获取render
          var ref = compileToFunctions(template, {
            outputSourceRange: "development" !== 'production',
            shouldDecodeNewlines: shouldDecodeNewlines,
            shouldDecodeNewlinesForHref: shouldDecodeNewlinesForHref,
            delimiters: options.delimiters,
            comments: options.comments
          }, this);
          var render = ref.render;
          var staticRenderFns = ref.staticRenderFns;
          // 将render设置到组件的选项上
          options.render = render;
          options.staticRenderFns = staticRenderFns;
  
          /* istanbul ignore if */
          if ( config.performance && mark) {
            mark('compile end');
            measure(("vue " + (this._name) + " compile"), 'compile', 'compile end');
          }
        }
      }
  
      // mount方法默认部分
      return mount.call(this, el, hydrating)
    };
  
    /**
     * Get outerHTML of elements, taking care
     * of SVG elements in IE as well.
     */
    function getOuterHTML(el) {
      if (el.outerHTML) {
        return el.outerHTML
      } else {
        var container = document.createElement('div');
        container.appendChild(el.cloneNode(true));
        return container.innerHTML
      }
    }
  
    Vue.compile = compileToFunctions;
  
    return Vue;
  
  })));
  //# sourceMappingURL=vue.js.map
  