regex password validation flutter code example

Example 1: Password validation in dart with RegExp

bool isPasswordCompliant(String password, [int minLength = 8]) {
  if (password == null || password.length < minLength) {
    return false;
  }

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

  return false;
}

Example 2: flutter regex validation

You could make the first part optional matching either a + or 0 followed by a 9. Then match 10 digits:

^(?:[+0]9)?[0-9]{10}$
^ Start of string
(?:[+0]9)? Optionally match a + or 0 followed by 9
[0-9]{10} Match 10 digits
$ End of string
Regex demo