simple copyWith method in Dart

main.dart

// simple copyWith method 
class Credentials {
  const Credentials({this.email = '', this.password = ''});
  final String email;
  final String password;

  Credentials copyWith({String? email, String? password}) {
    return Credentials(
      email: email ?? this.email,
      password: password ?? this.password,
    );
  }
  
  @override
  String toString() => "Credentials $email, $password";
}

void main() {
  final cred = Credentials();
  print(cred);
  final newCred = cred.copyWith(email: '[email protected]');
  print(newCred);
  final newCred2 = newCred.copyWith(password: 'asdfsf');
  print(newCred2);
}

output

Credentials , 
Credentials [email protected], 
Credentials [email protected], asdfsf