请教一个数组合并方面的问题

[Colorful]

let arr = [{a:21,b:22,c:5},{a:11,b:21,c:4},{a:31,b:'2a',c:4},{a:'1aaa',b:'2a',c:5}]

我想合并成

let arr2 = [{c:4,child:[{a:11,b:21,c:4},{a:31,b:'2a',c:4}]},{c:5,child:[{a:21,b:22,c:5},{a:'1aaa',b:'2a',c:5}]}];

就是把 C 4 相同的数据，整合到一个数组下面

[shintendo]

lodash.groupBy

[shintendo]

原生的话：[...Set(arr.map(x => x.c))].map(c => ({c, child: arr.filter(x => x.c === c)}))

[shintendo]

少了个 new
[...new Set(arr.map(x => x.c))].map(c => ({c, child: arr.filter(x => x.c === c)}))

[otakustay]

const groups = groupBy(arr, i => i.c);
Object.entries(groups).map(([c, child]) => ({c, child}));

[Colorful]

@shintendo 懂了，涨知识了，感谢厂

[Colorful]

第一次了解 groupBy 这个语法，太感谢了