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- 'use strict';
- var $ = require('../internals/export');
- var bind = require('../internals/function-bind-context');
- var aMap = require('../internals/a-map');
- var iterate = require('../internals/map-iterate');
-
- // `Map.prototype.findKey` method
- // https://github.com/tc39/proposal-collection-methods
- $({ target: 'Map', proto: true, real: true, forced: true }, {
- findKey: function findKey(callbackfn /* , thisArg */) {
- var map = aMap(this);
- var boundFunction = bind(callbackfn, arguments.length > 1 ? arguments[1] : undefined);
- var result = iterate(map, function (value, key) {
- if (boundFunction(value, key, map)) return { key: key };
- }, true);
- return result && result.key;
- }
- });
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