filterAsync.ts

filterAsync.ts

const filterAsync = <T>(arr: T[], fn: (x: T) => Promise<boolean>) =>
  mapAsync(arr, fn).then((arr2) => arr.filter((_, i) => Boolean(arr2[i])));

(async () => {
  console.log("START FILTER");
  const filtered = await filterAsync([1, 2, 3, 4], async (n) => {
    const x = await fakeFilter(n);
    return x;
  });
  useResult(filtered);
  console.log("END FILTER");
})();