chunk.js

function* chunkIterable(iterable, chunkSize) {
  const it = iterable[Symbol.iterator]();
  for (let i = 0; i !== -1; ) {
    const chunk = [];
    for (const limit = i + chunkSize; i < limit; ++i) {
      const { done, value } = it.next();
      if (done) {
        i = -1;
        break;
      }
      chunk.push(value);
    }
    yield chunk;
  }
}

function* chunkArray(array, chunkSize) {
  const limit = array.length;
  for (let i = 0; i < limit; i += chunkSize) {
    yield array.slice(i, i + chunkSize);
  }
}

function chunk(iterable, chunkSize) {
  if (!(chunkSize > 0)) {
    return [].values();
  }

  return Array.isArray(iterable)
    ? chunkArray(iterable, chunkSize)
    : chunkIterable(iterable, chunkSize);
}