Yield Promise.race()

yieldMany.js

async function* yieldMany(promises) {
  promises.forEach((p) => {
    return p.then((value) => {
      promises.splice(
        promises.findIndex((xp) => xp === p),
        1
      );
      return value;
    });
  });

  while (promises.length > 0) {
    yield await Promise.race(promises);
  }

  return "done";
}

const generator = yieldMany([
  new Promise((r) => setTimeout(() => r(1), 200)),
  new Promise((r) => r(2)),
  new Promise((r) => setTimeout(() => r(3), 500)),
]);

async function run() {
  console.log("result 1:", (await generator.next()).value);
  console.log("result 2:", (await generator.next()).value);
  console.log("result 3:", (await generator.next()).value);
  console.log("result 4:", (await generator.next()).value);
}
run();

// result 1: 2
// result 2: 1
// result 3: 3
// result 4: done