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