Find median from array of numbers (mutable, due to .sort())

median.js

function median(numbers) {
  const middle = (numbers.length + 1) / 2;
  const sorted = numbers.sort((a, b) => a - b);
  const isEven = sorted.length % 2 === 0;
  return isEven
    ? (sorted[middle - 1.5] + sorted[middle - 0.5]) / 2
    : sorted[middle - 1];
}