1  var baseGetTag = require('./_baseGetTag'),
 2      getPrototype = require('./_getPrototype'),
 3      isObjectLike = require('./isObjectLike');
 4  
 5  /** `Object#toString` result references. */
 6  var objectTag = '[object Object]';
 7  
 8  /** Used for built-in method references. */
 9  var funcProto = Function.prototype,
10      objectProto = Object.prototype;
11  
12  /** Used to resolve the decompiled source of functions. */
13  var funcToString = funcProto.toString;
14  
15  /** Used to check objects for own properties. */
16  var hasOwnProperty = objectProto.hasOwnProperty;
17  
18  /** Used to infer the `Object` constructor. */
19  var objectCtorString = funcToString.call(Object);
20  
21  /**
22   * Checks if `value` is a plain object, that is, an object created by the
23   * `Object` constructor or one with a `[[Prototype]]` of `null`.
24   *
25   * @static
26   * @memberOf _
27   * @since 0.8.0
28   * @category Lang
29   * @param {*} value The value to check.
30   * @returns {boolean} Returns `true` if `value` is a plain object, else `false`.
31   * @example
32   *
33   * function Foo() {
34   *   this.a = 1;
35   * }
36   *
37   * _.isPlainObject(new Foo);
38   * // => false
39   *
40   * _.isPlainObject([1, 2, 3]);
41   * // => false
42   *
43   * _.isPlainObject({ 'x': 0, 'y': 0 });
44   * // => true
45   *
46   * _.isPlainObject(Object.create(null));
47   * // => true
48   */
49  function isPlainObject(value) {
50    if (!isObjectLike(value) || baseGetTag(value) != objectTag) {
51      return false;
52    }
53    var proto = getPrototype(value);
54    if (proto === null) {
55      return true;
56    }
57    var Ctor = hasOwnProperty.call(proto, 'constructor') && proto.constructor;
58    return typeof Ctor == 'function' && Ctor instanceof Ctor &&
59      funcToString.call(Ctor) == objectCtorString;
60  }
61  
62  module.exports = isPlainObject;