Function groupBy

Collect the items of the iterator into a map of arrays keyed by the return value of your key generator function.

import { pipe } from "yta";
import { groupBy, of } from "yta/async";

await pipe(
  of(5, 42, 101, 13, 2)
  groupBy((n) => (n % 2 === 0 ? "even" : "odd")),
  async (entries) => Object.fromEntries(await entries),
);
// => { "odd": [5, 101, 13], "even": [42, 2] }
Copy

See also:

The native Map object