32 lines
1.1 KiB
JavaScript
32 lines
1.1 KiB
JavaScript
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'use strict';
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var bind = require('../internals/function-bind-context');
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var uncurryThis = require('../internals/function-uncurry-this');
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var IndexedObject = require('../internals/indexed-object');
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var toObject = require('../internals/to-object');
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var lengthOfArrayLike = require('../internals/length-of-array-like');
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var MapHelpers = require('../internals/map-helpers');
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var Map = MapHelpers.Map;
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var mapGet = MapHelpers.get;
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var mapHas = MapHelpers.has;
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var mapSet = MapHelpers.set;
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var push = uncurryThis([].push);
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// `Array.prototype.groupToMap` method
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// https://github.com/tc39/proposal-array-grouping
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module.exports = function groupToMap(callbackfn /* , thisArg */) {
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var O = toObject(this);
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var self = IndexedObject(O);
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var boundFunction = bind(callbackfn, arguments.length > 1 ? arguments[1] : undefined);
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var map = new Map();
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var length = lengthOfArrayLike(self);
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var index = 0;
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var key, value;
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for (;length > index; index++) {
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value = self[index];
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key = boundFunction(value, index, O);
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if (mapHas(map, key)) push(mapGet(map, key), value);
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else mapSet(map, key, [value]);
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} return map;
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};
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