| 1 | 'use strict';
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| 2 | var $ = require('../internals/export');
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| 3 | var bind = require('../internals/function-bind-context');
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| 4 | var aMap = require('../internals/a-map');
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| 5 | var MapHelpers = require('../internals/map-helpers');
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| 6 | var iterate = require('../internals/map-iterate');
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| 7 |
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| 8 | var Map = MapHelpers.Map;
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| 9 | var set = MapHelpers.set;
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| 10 |
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| 11 | // `Map.prototype.mapKeys` method
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| 12 | // https://github.com/tc39/proposal-collection-methods
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| 13 | $({ target: 'Map', proto: true, real: true, forced: true }, {
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| 14 | mapKeys: function mapKeys(callbackfn /* , thisArg */) {
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| 15 | var map = aMap(this);
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| 16 | var boundFunction = bind(callbackfn, arguments.length > 1 ? arguments[1] : undefined);
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| 17 | var newMap = new Map();
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| 18 | iterate(map, function (value, key) {
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| 19 | set(newMap, boundFunction(value, key, map), value);
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| 20 | });
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| 21 | return newMap;
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| 22 | }
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| 23 | });
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