| 'use strict'; |
| var $ = require('../internals/export'); |
| var IS_PURE = require('../internals/is-pure'); |
| var anObject = require('../internals/an-object'); |
| var bind = require('../internals/bind-context'); |
| var getMapIterator = require('../internals/get-map-iterator'); |
| var iterate = require('../internals/iterate'); |
| |
| // `Map.prototype.findKey` method |
| // https://github.com/tc39/proposal-collection-methods |
| $({ target: 'Map', proto: true, real: true, forced: IS_PURE }, { |
| findKey: function findKey(callbackfn /* , thisArg */) { |
| var map = anObject(this); |
| var iterator = getMapIterator(map); |
| var boundFunction = bind(callbackfn, arguments.length > 1 ? arguments[1] : undefined, 3); |
| return iterate(iterator, function (key, value) { |
| if (boundFunction(value, key, map)) return iterate.stop(key); |
| }, undefined, true, true).result; |
| } |
| }); |