72 lines
2.2 KiB
JavaScript
72 lines
2.2 KiB
JavaScript
var baseForIn = require('../internal/baseForIn'),
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isArguments = require('./isArguments'),
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isObjectLike = require('../internal/isObjectLike');
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/** `Object#toString` result references. */
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var objectTag = '[object Object]';
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/** Used for native method references. */
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var objectProto = Object.prototype;
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/** Used to check objects for own properties. */
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var hasOwnProperty = objectProto.hasOwnProperty;
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/**
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* Used to resolve the [`toStringTag`](http://ecma-international.org/ecma-262/6.0/#sec-object.prototype.tostring)
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* of values.
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*/
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var objToString = objectProto.toString;
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/**
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* Checks if `value` is a plain object, that is, an object created by the
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* `Object` constructor or one with a `[[Prototype]]` of `null`.
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*
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* **Note:** This method assumes objects created by the `Object` constructor
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* have no inherited enumerable properties.
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*
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* @static
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* @memberOf _
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* @category Lang
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* @param {*} value The value to check.
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* @returns {boolean} Returns `true` if `value` is a plain object, else `false`.
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* @example
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*
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* function Foo() {
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* this.a = 1;
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* }
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*
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* _.isPlainObject(new Foo);
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* // => false
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*
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* _.isPlainObject([1, 2, 3]);
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* // => false
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*
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* _.isPlainObject({ 'x': 0, 'y': 0 });
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* // => true
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*
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* _.isPlainObject(Object.create(null));
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* // => true
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*/
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function isPlainObject(value) {
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var Ctor;
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// Exit early for non `Object` objects.
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if (!(isObjectLike(value) && objToString.call(value) == objectTag && !isArguments(value)) ||
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(!hasOwnProperty.call(value, 'constructor') && (Ctor = value.constructor, typeof Ctor == 'function' && !(Ctor instanceof Ctor)))) {
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return false;
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}
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// IE < 9 iterates inherited properties before own properties. If the first
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// iterated property is an object's own property then there are no inherited
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// enumerable properties.
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var result;
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// In most environments an object's own properties are iterated before
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// its inherited properties. If the last iterated property is an object's
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// own property then there are no inherited enumerable properties.
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baseForIn(value, function(subValue, key) {
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result = key;
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});
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return result === undefined || hasOwnProperty.call(value, result);
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}
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module.exports = isPlainObject;
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