split-promise-all.js

const to8Chunks = (previous, current, index) => {
	const remainder = index % 8;

	if (!previous[remainder]) {
		previous.push([]);
	}

	previous[remainder].push(current);
	return previous;
};

const main = async () => {
  const hugeArray = [];
  const hugeChunks = hugeArray.reduce(to8Chunks, []);
  let r = [];

  for (const hugeChunk of hugeChunks) {
    r = r.concat(await Promise.all(hugeChunk.map(doSomething)));
  }
};

main();