Validate Strong Passwords with Regex

function validateStrongPassword(password) {
  const strongPasswordRegex = new RegExp("^(?=.*[a-z])(?=.*[A-Z])(?=.*\\d)(?=.*[@$!%*?&])[A-Za-z\\d@$!%*?&]{8,}$");
  return strongPasswordRegex.test(password);
}

// Examples:
console.log(validateStrongPassword("MyStrongP@ss1")); // true
console.log(validateStrongPassword("weakpass"));      // false (no uppercase, no number, no special char, too short)
console.log(validateStrongPassword("OnlyWords"));     // false (no number, no special char)

How it works: This JavaScript snippet provides a regular expression to validate password strength. The regex `^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[@$!%*?&])[A-Za-z\d@$!%*?&]{8,}$` uses positive lookaheads (`(?=...)`) to assert the presence of at least one lowercase letter, one uppercase letter, one digit, and one special character (from the set `@$!%*?&`). It then ensures the password contains only allowed characters (`[A-Za-z\d@$!%*?&]`) and is at least 8 characters long (`{8,}`). The `test()` method returns `true` if the password matches the pattern, `false` otherwise.