function* likeFor(end, step = 1, start = 0) {
  for (let i = start; i < end; i += step) {
    yield i;
  }
}

function* twice() {
  yield* gena(10);
  yield* gena(20);
}

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

function* likeAsync() {
  console.log(1);
  let res1 = yield delay(2000);
  console.log(2, res1);
  let res2 = yield delay(2000);
  console.log(3, res2);
}

function run(likeAsync) {
  let iter = likeAsync();
  function next(result, err) {
    let value, done;
    if (!err) {
      [{ value, done }] = [iter.next(result)];
    } else {
      [{ value, done }] = [iter.throw(err)];
    }
    if (done) return;
    if (value && typeof value?.then === "function") {
      value.then(next, (err) => next(undefined, err));
    } else {
      next(value);
    }
  }
  next();
}

run(likeAsync);