function quickSortHelper(arrayInput, left, right) {
  let i = left;
  let j = right;
  let pivotPoint = arrayInput[Math.round((left + right) / 2)];

  // loop
  while (i <= j) {
     while (arrayInput[i] < pivotPoint) {
        i++;
     }
     while (arrayInput[j] > pivotPoint) {
         j--;
     }

     if (i <= j) {
         let tempStore = arrayInput[i];
         arrayInput[i] = arrayInput[j]'
         i++;
         arrayInput[j] = tempStore;
         j--;
      }
  }

  if (left < j) {
        quickSortHelper(arrayInput, left, j);
   }
  if (i < right) {
        quickSortHelper(arrayInput, i, right);
   }

   return arrayInput;
}

function quickSort(input) {
  return quickSortHelper(input, 0, input.length - 1);  
}

let myData = [24, 10, 17, 9, 5, 9, 1, 23, 300];
quickSort(myData);