32 lines
1014 B
JavaScript
32 lines
1014 B
JavaScript
|
'use strict';
|
||
|
|
var $ = require('../internals/export');
|
||
|
|
var uncurryThis = require('../internals/function-uncurry-this');
|
||
|
|
var aCallable = require('../internals/a-callable');
|
||
|
|
var requireObjectCoercible = require('../internals/require-object-coercible');
|
||
|
|
var iterate = require('../internals/iterate');
|
||
|
|
var MapHelpers = require('../internals/map-helpers');
|
||
|
|
var IS_PURE = require('../internals/is-pure');
|
||
|
|
|
||
|
|
var Map = MapHelpers.Map;
|
||
|
|
var has = MapHelpers.has;
|
||
|
|
var get = MapHelpers.get;
|
||
|
|
var set = MapHelpers.set;
|
||
|
|
var push = uncurryThis([].push);
|
||
|
|
|
||
|
|
// `Map.groupBy` method
|
||
|
|
// https://github.com/tc39/proposal-array-grouping
|
||
|
|
$({ target: 'Map', stat: true, forced: IS_PURE }, {
|
||
|
|
groupBy: function groupBy(items, callbackfn) {
|
||
|
|
requireObjectCoercible(items);
|
||
|
|
aCallable(callbackfn);
|
||
|
|
var map = new Map();
|
||
|
|
var k = 0;
|
||
|
|
iterate(items, function (value) {
|
||
|
|
var key = callbackfn(value, k++);
|
||
|
|
if (!has(map, key)) set(map, key, [value]);
|
||
|
|
else push(get(map, key), value);
|
||
|
|
});
|
||
|
|
return map;
|
||
|
|
}
|
||
|
|
});
|