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