HORIZON PROJECT

var baseGetTag = require('./_baseGetTag'),

    getPrototype = require('./_getPrototype'),

    isObjectLike = require('./isObjectLike');

/** `Object#toString` result references. */

var objectTag = '[object Object]';

/** Used for built-in method references. */

var funcProto = Function.prototype,

    objectProto = Object.prototype;

/** Used to resolve the decompiled source of functions. */

var funcToString = funcProto.toString;

/** Used to check objects for own properties. */

var hasOwnProperty = objectProto.hasOwnProperty;

/** Used to infer the `Object` constructor. */

var objectCtorString = funcToString.call(Object);

/**

 * Checks if `value` is a plain object, that is, an object created by the

 * `Object` constructor or one with a `[[Prototype]]` of `null`.

 *

 * @static

 * @memberOf _

 * @since 0.8.0

 * @category Lang

 * @param {*} value The value to check.

 * @returns {boolean} Returns `true` if `value` is a plain object, else `false`.

 * @example

 *

 * function Foo() {

 *   this.a = 1;

 * }

 *

 * _.isPlainObject(new Foo);

 * // => false

 *

 * _.isPlainObject([1, 2, 3]);

 * // => false

 *

 * _.isPlainObject({ 'x': 0, 'y': 0 });

 * // => true

 *

 * _.isPlainObject(Object.create(null));

 * // => true

 */

function isPlainObject(value) {

  if (!isObjectLike(value) || baseGetTag(value) != objectTag) {

    return false;

  }

  var proto = getPrototype(value);

  if (proto === null) {

    return true;

  }

  var Ctor = hasOwnProperty.call(proto, 'constructor') && proto.constructor;

  return typeof Ctor == 'function' && Ctor instanceof Ctor &&

    funcToString.call(Ctor) == objectCtorString;

}

module.exports = isPlainObject;