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39 lines
1.2 KiB
39 lines
1.2 KiB
4 weeks ago
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'use strict';
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var $ = require('../internals/export');
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var uncurryThis = require('../internals/function-uncurry-this');
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var aCallable = require('../internals/a-callable');
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var requireObjectCoercible = require('../internals/require-object-coercible');
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var iterate = require('../internals/iterate');
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var MapHelpers = require('../internals/map-helpers');
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var IS_PURE = require('../internals/is-pure');
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var fails = require('../internals/fails');
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var Map = MapHelpers.Map;
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var has = MapHelpers.has;
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var get = MapHelpers.get;
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var set = MapHelpers.set;
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var push = uncurryThis([].push);
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var DOES_NOT_WORK_WITH_PRIMITIVES = IS_PURE || fails(function () {
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return Map.groupBy('ab', function (it) {
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return it;
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}).get('a').length !== 1;
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});
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// `Map.groupBy` method
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// https://github.com/tc39/proposal-array-grouping
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$({ target: 'Map', stat: true, forced: IS_PURE || DOES_NOT_WORK_WITH_PRIMITIVES }, {
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groupBy: function groupBy(items, callbackfn) {
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requireObjectCoercible(items);
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aCallable(callbackfn);
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var map = new Map();
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var k = 0;
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iterate(items, function (value) {
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var key = callbackfn(value, k++);
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if (!has(map, key)) set(map, key, [value]);
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else push(get(map, key), value);
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});
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return map;
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}
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});
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