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var baseForIn = require('../internal/baseForIn'),
isArguments = require('./isArguments'),
isObjectLike = require('../internal/isObjectLike');
/** `Object#toString` result references. */
var objectTag = '[object Object]';
/** Used for native method references. */
var objectProto = Object.prototype;
/** Used to check objects for own properties. */
var hasOwnProperty = objectProto.hasOwnProperty;
/**
* Used to resolve the [`toStringTag`](http://ecma-international.org/ecma-262/6.0/#sec-object.prototype.tostring)
* of values.
*/
var objToString = objectProto.toString;
/**
* Checks if `value` is a plain object, that is, an object created by the
* `Object` constructor or one with a `[[Prototype]]` of `null`.
*
* **Note:** This method assumes objects created by the `Object` constructor
* have no inherited enumerable properties.
*
* @static
* @memberOf _
* @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) {
var Ctor;
// Exit early for non `Object` objects.
if (!(isObjectLike(value) && objToString.call(value) == objectTag && !isArguments(value)) ||
(!hasOwnProperty.call(value, 'constructor') && (Ctor = value.constructor, typeof Ctor == 'function' && !(Ctor instanceof Ctor)))) {
return false;
}
// IE < 9 iterates inherited properties before own properties. If the first
// iterated property is an object's own property then there are no inherited
// enumerable properties.
var result;
// In most environments an object's own properties are iterated before
// its inherited properties. If the last iterated property is an object's
// own property then there are no inherited enumerable properties.
baseForIn(value, function(subValue, key) {
result = key;
});
return result === undefined || hasOwnProperty.call(value, result);
}
module.exports = isPlainObject;
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