Chunk Promise Array with Timeout

chunk-promises.ts

function chunkPromises(array: Promise<any>[], size: number, delay: number): Promise<any> {
  let p: Promise<any> = Promise.resolve();
  let results = [];
  for (var i = 0; i < array.length; i += size) {
    p = p.then(() => i > 0 ? new Promise((r) => setTimeout(r, delay)) : true)
      .then(() => Promise.all(array.slice(i, i + size)))
      .then((r) => results.push(...r));
  }
  return p;
}