Arrays & Array Methods (map, filter, reduce)

const nums = [3, 1, 4, 1, 5, 9, 2, 6, 5];
const sorted = [...nums].sort((a, b) => {
  if (a % 2 === b % 2) return a - b;
  return a % 2 - b % 2;
});

Sort by value only
Sort even numbers first
This implements custom sort with even numbers first: 1) Creates array copy with spread operator, 2) Compares numbers' parity using modulo, 3) If same parity, sorts by value, 4) Even numbers come before odd numbers, 5) Maintains relative order within each parity group, 6) Doesn't modify original array, 7) Common pattern for complex sorting requirements, 8) Useful for specialized data presentation.
Sort odd numbers first
Sort by remainder