CODE EXAMPLE FOR DART

string validation in dart

bool isPasswordCompliant(String password, [int minLength = 6]) {
  if (password == null || password.isEmpty) {
    return false;
  }

  bool hasUppercase = password.contains(new RegExp(r'[A-Z]'));
  bool hasDigits = password.contains(new RegExp(r'[0-9]'));
  bool hasLowercase = password.contains(new RegExp(r'[a-z]'));
  bool hasSpecialCharacters = password.contains(new RegExp(r'[!@#$%^&*(),.?":{}|<>]'));
  bool hasMinLength = password.length > minLength;

  return hasDigits & hasUppercase & hasLowercase & hasSpecialCharacters & hasMinLength;
}