programa que haga un ordenamiento mezcla natural

Script

function natural_merge_sort(arr){
  if(arr.length < 2){
    return arr;
  }
  var middle = Math.round(arr.length/2);
  var left = arr.slice(0, middle);
  var right = arr.slice(middle, arr.length);
  return merge(natural_merge_sort(left), natural_merge_sort(right));
}

function merge(left, right)
{
  var result  = [];
  while ((left.length > 0) && (right.length > 0))
  {
    if (left[0] <= right[0])
    {
      result.push(left.shift());
    }
    else
    {
      result.push(right.shift());
    }
  }
  while (left.length > 0)
    result.push(left.shift());

  while (right.length > 0)
    result.push(right.shift());

  return result;
}

natural_merge_sort([8,7,6