JavaScript/Sorts/quickSort.js

/*
* Quick sort is a comparison sorting algorithm that uses a divide and conquer strategy.
* For more information see here: https://en.wikipedia.org/wiki/Quicksort
*/
function quickSort(items) {

  var length = items.length;

  if (length <= 1) {
    return items;
  }
  var PIVOT = items[0];
  var GREATER = [];
  var LESSER = [];

  for (var i = 1; i < length; i++) {
    if (items[i] > PIVOT) {
      GREATER.push(items[i]);
    } else {
      LESSER.push(items[i]);
    }
  }

  var sorted = quickSort(LESSER);
  sorted.push(PIVOT);
  sorted = sorted.concat(quickSort(GREATER));
  
  return sorted;
}

//Implementation of quick sort

var ar = [0, 5, 3, 2, 2];
//Array before Sort
console.log(ar);
ar = quickSort(ar);
//Array after sort
console.log(ar);