2 var $ = require('../internals/export');
3 var IS_PURE = require('../internals/is-pure');
4 var anObject = require('../internals/an-object');
5 var bind = require('../internals/function-bind-context');
6 var getMapIterator = require('../internals/get-map-iterator');
7 var iterate = require('../internals/iterate');
9 // `Map.prototype.findKey` method
10 // https://github.com/tc39/proposal-collection-methods
11 $({ target: 'Map', proto: true, real: true, forced: IS_PURE }, {
12 findKey: function findKey(callbackfn /* , thisArg */) {
13 var map = anObject(this);
14 var iterator = getMapIterator(map);
15 var boundFunction = bind(callbackfn, arguments.length > 1 ? arguments[1] : undefined);
16 return iterate(iterator, function (key, value, stop) {
17 if (boundFunction(value, key, map)) return stop(key);
18 }, { AS_ENTRIES: true, IS_ITERATOR: true, INTERRUPTED: true }).result;