javascript で並列 worker

a.mjs

// cf. https://maximorlov.com/parallel-tasks-with-pure-javascript/
import { setTimeout } from 'node:timers/promises';

async function doWork(iterator, i) {
  for await (const value of iterator) {
    await setTimeout(1000);
    console.log(`worker ${i}: ${value}`);
  }
  console.log(`worker ${i} finish`)
}

const ar = [...Array(20)].map((_, i) => i)
const iterator = ar.values();


const workers = new Array(3).fill(iterator).map(doWork);

await Promise.allSettled(workers);

console.log('Done!');