quick_sort.js

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

  const pivot = arr[Math.floor(Math.random() * arr.length)];

  let left = [];
  let equal = [];
  let right = [];

  for (let element of arr) {
    if (element > pivot) right.push(element);
    else if (element < pivot) left.push(element);
    else equal.push(element);
  }

  return quickSort(left)
    .concat(equal)
    .concat(quickSort(right));
};