chunked-async-iterator.js

async function* generate(count) {
  for (let i = 1; i <= count; i++) {
    await new Promise((resolve) => setTimeout(resolve, 1000));
    yield i;
  }
}

async function* chunkAsync(iterator, size) {
  let items = [];
  for await (const item of iterator) {
    items.push(item);
    if (items.length >= size) {
      yield items;
      items = [];
    }
  }
  if (items.length > 0) yield items;
}

const main = async () => {
  const begin = Date.now();
  for await (const item of chunkAsync(generate(10), 2)) {
    console.log(Date.now() - begin, item);
  }
};

main()
  .then(() => process.exit(0))
  .catch((err) => {
    console.error(err);
    process.exit(1);
  });