Implementing Quicksort in JavaScript

default.js

const defaultComparator = (a, b) => {
  if (a < b) {
    return -1;
  }
  if (a > b) {
    return 1;
  }
  return 0;
};

const quickSort = (
  unsortedArray,
  comparator = defaultComparator
) => {
  const sortedArray = TODO(unsortedArray);
  return sortedArray;
};