text: var arrayEach = require('../internal/arrayEach'),
      isArguments = require('../lang/isArguments'),
      isArray = require('../lang/isArray'),
      isFunction = require('../lang/isFunction'),
      isIndex = require('../internal/isIndex'),
      isLength = require('../internal/isLength'),
      isObject = require('../lang/isObject'),
      isString = require('../lang/isString'),
      support = require('../support');
  
  /** `Object#toString` result references. */
  var arrayTag = '[object Array]',
      boolTag = '[object Boolean]',
      dateTag = '[object Date]',
      errorTag = '[object Error]',
      funcTag = '[object Function]',
      numberTag = '[object Number]',
      objectTag = '[object Object]',
      regexpTag = '[object RegExp]',
      stringTag = '[object String]';
  
  /** Used to fix the JScript `[[DontEnum]]` bug. */
  var shadowProps = [
    'constructor', 'hasOwnProperty', 'isPrototypeOf', 'propertyIsEnumerable',
    'toLocaleString', 'toString', 'valueOf'
  ];
  
  /** Used for native method references. */
  var errorProto = Error.prototype,
      objectProto = Object.prototype,
      stringProto = String.prototype;
  
  /** Used to check objects for own properties. */
  var hasOwnProperty = objectProto.hasOwnProperty;
  
  /**
   * Used to resolve the [`toStringTag`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.prototype.tostring)
   * of values.
   */
  var objToString = objectProto.toString;
  
  /** Used to avoid iterating over non-enumerable properties in IE < 9. */
  var nonEnumProps = {};
  nonEnumProps[arrayTag] = nonEnumProps[dateTag] = nonEnumProps[numberTag] = { 'constructor': true, 'toLocaleString': true, 'toString': true, 'valueOf': true };
  nonEnumProps[boolTag] = nonEnumProps[stringTag] = { 'constructor': true, 'toString': true, 'valueOf': true };
  nonEnumProps[errorTag] = nonEnumProps[funcTag] = nonEnumProps[regexpTag] = { 'constructor': true, 'toString': true };
  nonEnumProps[objectTag] = { 'constructor': true };
  
  arrayEach(shadowProps, function(key) {
    for (var tag in nonEnumProps) {
      if (hasOwnProperty.call(nonEnumProps, tag)) {
        var props = nonEnumProps[tag];
        props[key] = hasOwnProperty.call(props, key);
      }
    }
  });
  
  /**
   * Creates an array of the own and inherited enumerable property names of `object`.
   *
   * **Note:** Non-object values are coerced to objects.
   *
   * @static
   * @memberOf _
   * @category Object
   * @param {Object} object The object to inspect.
   * @returns {Array} Returns the array of property names.
   * @example
   *
   * function Foo() {
   *   this.a = 1;
   *   this.b = 2;
   * }
   *
   * Foo.prototype.c = 3;
   *
   * _.keysIn(new Foo);
   * // => ['a', 'b', 'c'] (iteration order is not guaranteed)
   */
  function keysIn(object) {
    if (object == null) {
      return [];
    }
    if (!isObject(object)) {
      object = Object(object);
    }
    var length = object.length;
  
    length = (length && isLength(length) &&
      (isArray(object) || (support.nonEnumStrings && isString(object)) ||
        (support.nonEnumArgs && isArguments(object))) && length) || 0;
  
    var Ctor = object.constructor,
        index = -1,
        proto = (isFunction(Ctor) && Ctor.prototype) || objectProto,
        isProto = proto === object,
        result = Array(length),
        skipIndexes = length > 0,
        skipErrorProps = support.enumErrorProps && (object === errorProto || object instanceof Error),
        skipProto = support.enumPrototypes && isFunction(object);
  
    while (++index < length) {
      result[index] = (index + '');
    }
    // lodash skips the `constructor` property when it infers it is iterating
    // over a `prototype` object because IE < 9 can't set the `[[Enumerable]]`
    // attribute of an existing property and the `constructor` property of a
    // prototype defaults to non-enumerable.
    for (var key in object) {
      if (!(skipProto && key == 'prototype') &&
          !(skipErrorProps && (key == 'message' || key == 'name')) &&
          !(skipIndexes && isIndex(key, length)) &&
          !(key == 'constructor' && (isProto || !hasOwnProperty.call(object, key)))) {
        result.push(key);
      }
    }
    if (support.nonEnumShadows && object !== objectProto) {
      var tag = object === stringProto ? stringTag : (object === errorProto ? errorTag : objToString.call(object)),
          nonEnums = nonEnumProps[tag] || nonEnumProps[objectTag];
  
      if (tag == objectTag) {
        proto = objectProto;
      }
      length = shadowProps.length;
      while (length--) {
        key = shadowProps[length];
        var nonEnum = nonEnums[key];
        if (!(isProto && nonEnum) &&
            (nonEnum ? hasOwnProperty.call(object, key) : object[key] !== proto[key])) {
          result.push(key);
        }
      }
    }
    return result;
  }
  
  module.exports = keysIn;
  