quick sort

qsort.js

const arr = [1, 4, 2, 5, 200, 6, 9]

const qsort = (arr) => {
  if (arr.length < 2) {
    return arr
  } else {
    const pivot = arr[Math.floor(Math.random() * arr.length)]
    const less = arr.filter(value => value < pivot)
    const greater = arr.filter(value => value > pivot)

    return [...qsort(less), pivot, ...qsort(greater)]
  }
}

console.log(qsort(arr))