function validateEmail(email) {
  const re = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
  return re.test(email);
}

function formatGreeting(timeOfDay, name) {
  return `Good ${timeOfDay}, welcome to ${name}'s portfolio!`;
}

if (typeof module !== 'undefined' && module.exports) {
  module.exports = { validateEmail, formatGreeting };
}