Using map() on an iterator

Question

Say we have a Map: let m = new Map();, using m.values() returns a map iterator.

But I can\'t use forEach() or map() o

Answer 1

There is a proposal, that is bringing multiple helper functions to Iterator: https://github.com/tc39/proposal-iterator-helpers (rendered)

You can use it today by utilizing core-js:

import { from as iterFrom } from "core-js-pure/features/iterator";

// or if it's working for you:
// import iterFrom from "core-js-pure/features/iterator/from";

let m = new Map();

m.set("13", 37);
m.set("42", 42);

const arr = iterFrom(m.values())
  .map((val) => val * 2)
  .toArray();

// prints "[74, 84]"
console.log(arr);