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- 'use strict';
- var $ = require('../internals/export');
- var call = require('../internals/function-call');
- var iterate = require('../internals/iterate');
- var aCallable = require('../internals/a-callable');
- // `Map.keyBy` method
- // https://github.com/tc39/proposal-collection-methods
- $({ target: 'Map', stat: true, forced: true }, {
- keyBy: function keyBy(iterable, keyDerivative) {
- var newMap = new this();
- aCallable(keyDerivative);
- var setter = aCallable(newMap.set);
- iterate(iterable, function (element) {
- call(setter, newMap, keyDerivative(element), element);
- });
- return newMap;
- }
- });
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