Add methods or values to enum in dart

Question

In java when you are defining an enum you can do something similar to the following. Is this possible in Dart?

enum blah {
  one(1), two(2);
  final num valu         


        

Answer 1

Dart enums are used only for the simplest cases. If you need more powerful or more flexible enums, use classes with static const fields like shown in https://stackoverflow.com/a/15854550/217408

This way you can add whatever you need.

Answer 2

extension is good, but it cannot add static methods. If you want to do something like MyType.parse(string), consider using a class with static const fields instead (as Günter Zöchbauer suggested before).

Here is an example

class PaymentMethod {
  final String string;
  const PaymentMethod._(this.string);

  static const online = PaymentMethod._('online');
  static const transfer = PaymentMethod._('transfer');
  static const cash = PaymentMethod._('cash');

  static const values = [online, transfer, cash];

  static PaymentMethod parse(String value) {
    switch (value) {
      case 'online':
        return PaymentMethod.online;
        break;
      case 'transfer':
        return PaymentMethod.transfer;
        break;
      case 'cash':
        return PaymentMethod.cash;
      default:
        print('got error, invalid payment type $value');
        return null;
    }
  }

  @override
  String toString() {
    return 'PaymentMethod.$string';
  }
}

I found this much handier than using a helper function.

final method = PaymentMethod.parse('online');
assert(method == PaymentMethod.online);