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_getTag.js
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_getTag.js
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define(['./_DataView', './_Map', './_Promise', './_Set', './_WeakMap', './_baseGetTag', './_toSource'], function(DataView, Map, Promise, Set, WeakMap, baseGetTag, toSource) {
/** Used as a safe reference for `undefined` in pre-ES5 environments. */
var undefined;
/** `Object#toString` result references. */
var mapTag = '[object Map]',
objectTag = '[object Object]',
promiseTag = '[object Promise]',
setTag = '[object Set]',
weakMapTag = '[object WeakMap]';
var dataViewTag = '[object DataView]';
/** Used for built-in method references. */
var objectProto = Object.prototype;
/**
* Used to resolve the
* [`toStringTag`](http://ecma-international.org/ecma-262/7.0/#sec-object.prototype.tostring)
* of values.
*/
var objectToString = objectProto.toString;
/** Used to detect maps, sets, and weakmaps. */
var dataViewCtorString = toSource(DataView),
mapCtorString = toSource(Map),
promiseCtorString = toSource(Promise),
setCtorString = toSource(Set),
weakMapCtorString = toSource(WeakMap);
/**
* Gets the `toStringTag` of `value`.
*
* @private
* @param {*} value The value to query.
* @returns {string} Returns the `toStringTag`.
*/
var getTag = baseGetTag;
// Fallback for data views, maps, sets, and weak maps in IE 11,
// for data views in Edge < 14, and promises in Node.js.
if ((DataView && getTag(new DataView(new ArrayBuffer(1))) != dataViewTag) ||
(Map && getTag(new Map) != mapTag) ||
(Promise && getTag(Promise.resolve()) != promiseTag) ||
(Set && getTag(new Set) != setTag) ||
(WeakMap && getTag(new WeakMap) != weakMapTag)) {
getTag = function(value) {
var result = objectToString.call(value),
Ctor = result == objectTag ? value.constructor : undefined,
ctorString = Ctor ? toSource(Ctor) : undefined;
if (ctorString) {
switch (ctorString) {
case dataViewCtorString: return dataViewTag;
case mapCtorString: return mapTag;
case promiseCtorString: return promiseTag;
case setCtorString: return setTag;
case weakMapCtorString: return weakMapTag;
}
}
return result;
};
}
return getTag;
});