/**
 * Determines whether a given number is a perfect square.
 *
 * @param {number} n - The number to test.
 * @returns {boolean} True if n is a non‑negative integer that is a perfect square, otherwise false.
 */
export function isPerfectSquare(n) {
  if (typeof n !== "number" || !Number.isFinite(n)) return false;
  if (!Number.isInteger(n)) return false;
  if (n < 0) return false;

  const root = Math.sqrt(n);
  return Number.isInteger(root);
}