1 var Map = require('./_Map'),
2 Set = require('./_Set'),
3 WeakMap = require('./_WeakMap');
5 /** `Object#toString` result references. */
6 var mapTag = '[object Map]',
7 objectTag = '[object Object]',
8 setTag = '[object Set]',
9 weakMapTag = '[object WeakMap]';
11 /** Used for built-in method references. */
12 var objectProto = Object.prototype;
14 /** Used to resolve the decompiled source of functions. */
15 var funcToString = Function.prototype.toString;
18 * Used to resolve the [`toStringTag`](http://ecma-international.org/ecma-262/6.0/#sec-object.prototype.tostring)
21 var objectToString = objectProto.toString;
23 /** Used to detect maps, sets, and weakmaps. */
24 var mapCtorString = Map ? funcToString.call(Map) : '',
25 setCtorString = Set ? funcToString.call(Set) : '',
26 weakMapCtorString = WeakMap ? funcToString.call(WeakMap) : '';
29 * Gets the `toStringTag` of `value`.
32 * @param {*} value The value to query.
33 * @returns {string} Returns the `toStringTag`.
35 function getTag(value) {
36 return objectToString.call(value);
39 // Fallback for IE 11 providing `toStringTag` values for maps, sets, and weakmaps.
40 if ((Map && getTag(new Map) != mapTag) ||
41 (Set && getTag(new Set) != setTag) ||
42 (WeakMap && getTag(new WeakMap) != weakMapTag)) {
43 getTag = function(value) {
44 var result = objectToString.call(value),
45 Ctor = result == objectTag ? value.constructor : null,
46 ctorString = typeof Ctor == 'function' ? funcToString.call(Ctor) : '';
50 case mapCtorString: return mapTag;
51 case setCtorString: return setTag;
52 case weakMapCtorString: return weakMapTag;
59 module.exports = getTag;