core-js/modules/es.weak-map.js

Standard library

'use strict';
var redefineAll = require('../internals/redefine-all');
var InternalMetadataModule = require('../internals/internal-metadata');
var weak = require('../internals/collection-weak');
var isObject = require('../internals/is-object');
var fails = require('../internals/fails');
var enforceIternalState = require('../internals/internal-state').enforce;
var WEAK_MAP = 'WeakMap';
var isExtensible = Object.isExtensible;
var test = {};
var InternalWeakMap;

var wrapper = function (get) {
  return function WeakMap() {
    return get(this, arguments.length > 0 ? arguments[0] : undefined);
  };
};

// `WeakMap` constructor
// https://tc39.github.io/ecma262/#sec-weakmap-constructor
var $WeakMap = module.exports = require('../internals/collection')(WEAK_MAP, wrapper, weak, true, true);

// IE11 WeakMap frozen keys fix
if (fails(function () { return new $WeakMap().set((Object.freeze || Object)(test), 7).get(test) != 7; })) {
  InternalWeakMap = weak.getConstructor(wrapper, WEAK_MAP, true);
  InternalMetadataModule.REQUIRED = true;
  var WeakMapPrototype = $WeakMap.prototype;
  var nativeDelete = WeakMapPrototype['delete'];
  var nativeHas = WeakMapPrototype.has;
  var nativeGet = WeakMapPrototype.get;
  var nativeSet = WeakMapPrototype.set;
  redefineAll(WeakMapPrototype, {
    'delete': function (key) {
      if (isObject(key) && !isExtensible(key)) {
        var state = enforceIternalState(this);
        if (!state.frozen) state.frozen = new InternalWeakMap();
        return nativeDelete.call(this, key) || state.frozen['delete'](key);
      } return nativeDelete.call(this, key);
    },
    has: function has(key) {
      if (isObject(key) && !isExtensible(key)) {
        var state = enforceIternalState(this);
        if (!state.frozen) state.frozen = new InternalWeakMap();
        return nativeHas.call(this, key) || state.frozen.has(key);
      } return nativeHas.call(this, key);
    },
    get: function get(key) {
      if (isObject(key) && !isExtensible(key)) {
        var state = enforceIternalState(this);
        if (!state.frozen) state.frozen = new InternalWeakMap();
        return nativeHas.call(this, key) ? nativeGet.call(this, key) : state.frozen.get(key);
      } return nativeGet.call(this, key);
    },
    set: function set(key, value) {
      if (isObject(key) && !isExtensible(key)) {
        var state = enforceIternalState(this);
        if (!state.frozen) state.frozen = new InternalWeakMap();
        nativeHas.call(this, key) ? nativeSet.call(this, key, value) : state.frozen.set(key, value);
      } else nativeSet.call(this, key, value);
      return this;
    }
  });
}