const quick_sort = (arr) => {
  if (arr.length < 2) {
    return arr;
  }

  const pivot = arr[0];
  const less = [];
  const greater = [];

  for (let i = 1; i < arr.length; i++) {
    const candidate = arr[i];
    if (candidate < pivot) {
      less.push(candidate)
    } else {
      greater.push(candidate);
    }
  }

  return [quick_sort(less), pivot, quick_sort(greater)].flat();
}

const res = quick_sort([1, 234, 21, 4, 211, 4, 63, 12, 84, 2])
console.log('res', res);