An implementation of quicksort in TypeScript - warning: this is probably bad

quickSort.ts

const MIN = -1e3;
const MAX = 1e3;
const SIZE = 1e6;

/**
 * Get a random number between min and max.
 *
 * @param min the minimum integer possible.
 * @param max the maximum integer possible.
 */
const getRandomNumber = (min: number, max: number): number =>
  Math.round((max - min) * Math.random() + min);

/**
 * Sort an unsorted array of integers.
 *
 * @param unsorted an unsorted array of integers.
 */
const quickSort = (unsorted: Array<number>): Array<number> => {
  if (unsorted.length < 2) {
    return unsorted;
  }

  const [pivot, ...rest] = unsorted;
  const left = [];
  const right = [];
  const center = [pivot];

  for (const val of rest) {
    if (val < pivot) {
      left.push(val);
    } else if (val === pivot) {
      center.push(val);
    } else {
      right.push(val);
    }
  }

  return [...quickSort(left), ...center, ...quickSort(right)];
};

const array = Array.from(Array(SIZE).keys()).map(() =>
  getRandomNumber(MIN, MAX)
);

const sorted = quickSort(array);
console.log('Unsorted:', array.length, array);
console.log('Sorted:', sorted.length, sorted);