27 lines
1.1 KiB
JavaScript
27 lines
1.1 KiB
JavaScript
'use strict';
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var $ = require('../internals/export');
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var IS_PURE = require('../internals/is-pure');
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var getBuiltIn = require('../internals/get-built-in');
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var anObject = require('../internals/an-object');
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var aFunction = require('../internals/a-function');
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var bind = require('../internals/function-bind-context');
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var speciesConstructor = require('../internals/species-constructor');
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var getMapIterator = require('../internals/get-map-iterator');
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var iterate = require('../internals/iterate');
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// `Map.prototype.mapKeys` method
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// https://github.com/tc39/proposal-collection-methods
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$({ target: 'Map', proto: true, real: true, forced: IS_PURE }, {
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mapKeys: function mapKeys(callbackfn /* , thisArg */) {
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var map = anObject(this);
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var iterator = getMapIterator(map);
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var boundFunction = bind(callbackfn, arguments.length > 1 ? arguments[1] : undefined, 3);
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var newMap = new (speciesConstructor(map, getBuiltIn('Map')))();
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var setter = aFunction(newMap.set);
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iterate(iterator, function (key, value) {
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setter.call(newMap, boundFunction(value, key, map), value);
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}, undefined, true, true);
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return newMap;
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}
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});
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