iteration.functions.js

import assert from "assert";
import each from "each";

const result = await each([
  // A synchronous function
  function(){ return 'a'; },
  // A synchronous function with the fat arrow syntax
  () => 'b',
  // An asynchronous function
  () => (
    new Promise((resolve) => resolve('c'))
  ),
  // An asynchronous function which resolves after some delay
  () => (
    new Promise((resolve) => setTimeout (() => resolve('d')), 100)
  ),
]);

assert.deepStrictEqual(
  result, 
  ['a', 'b', 'c', 'd']
);