quickSort.js

var quickSort = function(arr){
  if ( arr.length <= 1 ) {
    return arr;
  }
  var sampleIndex = Math.floor(arr.length/2),
    sample = arr.splice(sampleIndex, 1)[0],
    left = [],
    right = [];
  for (var i = 0; i < arr.length ; i++){
    if ( arr[i] < sample ) {
      left.push(arr[i])
    } else {
      right.push(arr[i])
    }
  }
  return quickSort(left).concat([sample], quickSort(right))
}