Write a sorting function that takes in an array of names and sorts them by last name either alphabetically (ASC) or reverse-alphabetically (DESC). injavascript code example

var numbers = [4, 2, 5, 1, 3];
numbers.sort(function(a, b) {
  return a - b;
});
console.log(numbers);

// [1, 2, 3, 4, 5]