function isValidUSPhoneNumber(phoneNumber) {
  // This regex validates common US phone number formats:
  // - (XXX) XXX-XXXX
  // - XXX-XXX-XXXX
  // - XXXXXXXXXX (ten digits only)
  // - Optionally allows for a leading '1' with or without a space/dash.
  const phoneRegex = /^(?:\+?1[\s\-]?)?\(?([0-9]{3})\)?[\s\-]?([0-9]{3})[\s\-]?([0-9]{4})$/;
  return phoneRegex.test(phoneNumber);
}

// Example Usage:
// const phone1 = "(123) 456-7890";
// const phone2 = "123-456-7890";
// const phone3 = "1234567890";
// const phone4 = "+1 123-456-7890";
// const phone5 = "555-NO-DIAL";
// console.log(`'${phone1}' is valid: ${isValidUSPhoneNumber(phone1)}`);
// console.log(`'${phone2}' is valid: ${isValidUSPhoneNumber(phone2)}`);
// console.log(`'${phone3}' is valid: ${isValidUSPhoneNumber(phone3)}`);
// console.log(`'${phone4}' is valid: ${isValidUSPhoneNumber(phone4)}`);
// console.log(`'${phone5}' is valid: ${isValidUSPhoneNumber(phone5)}`);