quicksort.js

/**
 * QuickSort
 *
 * @param {Array} arr Array to be sorted
 * @returns {Array} new array sorted
 */
var quickSort = function (arr) {
  'use strict';

    var sort = function (arr) {

        var less    = [],
            greater = [],
            pivot   = arr.splice(Math.floor(arr.length/2), 1),
            swapped = false;

        arr.forEach(function (val) {
            if (val < pivot) { less.push(val); }
            else { greater.push(val); }
        });

        swapped = (less.length || greater.length);

        return (swapped) ?

                [].concat(sort(less))
                  .concat(pivot)
                  .concat(sort(greater)) :

                [].concat(less)
                  .concat(pivot)
                  .concat(greater);

    };

    if (arr.length <= 1) { return arr; }

    return sort(arr);

};