hasUpperCaseAndNumber method

String? hasUpperCaseAndNumber()

hasUpperCaseAndNumber does exactly what it says will return null if valid and an error message if not. 'Password requires at least One Uppercase letter and One Number. It also requires at least 8 characters.'

Implementation

String? hasUpperCaseAndNumber() {
  if (this == null || this!.isEmpty) {
    return 'Please enter a password.';
  }
  if (!RegExp(r'^(?=.*?[A-Z])(?=.*?[a-z])(?=.*?[0-9]).{8,}$')
      .hasMatch(this!)) {
    return 'Password requires at least One Uppercase letter and One Number.\nIt also requires at least 8 characters.';
  }
  return null;
}