racePromisePool

1_racePromisePool.js

const delay = ms => new Promise(ok => setTimeout(() => ok(ms), ms));

;(async () => {
    const pool = [
        delay(2000),
        delay(1000),
        delay(3000),
        delay(500),
    ];

    for await (const res of racePromisePool(pool)) {
        // use `res` here
    }

})();

iterative.js

async function *racePromisePool([...prs] = []) {
  while(prs.length > 0) {
    let { val, idx }= await Promise.race(prs.map((p, idx) => p.then(val => ({ val, idx }))));
    prs.splice(idx, 1);
    yield val;
  }
}

recursive.js

async function* racePromisePool(prs = []) {
    if (prs.length == 0) return;
    let { val, idx } = await Promise.race(prs.map((p, idx) => p.then(val => ({ val, idx }))));
    yield val;
    yield* racePromisePool(prs.filter((p, i) => i !== idx));
}