githubmirror/lodash

_getTag.js
56 строк2 KB
John-David Dalton
Bump to v4.16.5.
31 окт 2016, 06:06
31 окт 2016, 06:06b58a63e
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 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 and promises in Node.js < 6.
  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 = baseGetTag(value),
          Ctor = result == objectTag ? value.constructor : undefined,
          ctorString = Ctor ? toSource(Ctor) : '';

      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;
});