I am using the following plugin: https://pub.dev/packages/freezed
I want to subclass a freezed data class to provide additional functionality in my data layer. So I have my data class which looks like:
import 'dart:ui';
import 'package:freezed_annotation/freezed_annotation.dart';
part 'card.freezed.dart';
@freezed
abstract class Card with _$Card {
factory Card({String text, Color color, List<String> categories}) = _Card;
}
Now I want to have this Card class as a super class to my CardModel so that the CardModel has access to the same fields, the copyWith method, value equality, ... But I have no Idea how to go about this. I am trying something like this:
import 'package:flutter/widgets.dart';
import 'package:growthdeck/features/card_deck/domain/entities/card.dart';
import '../../domain/entities/card.dart';
abstract class CardModel extends Card {
factory CardModel.fromMap(Map<String, dynamic> card) => Card(
text: card["text"],
color: Color(int.parse(card['color'])),
categories: card['categories'] as List<String>,
);
}
Which throws the following error:
package:growthdeck/features/card_deck/data/models/card_model.dart 11:9 new CardModel.fromMap
test/features/card_deck/data/models/card_model_test.dart 13:23 main.<fn>
type '_$_Card' is not a subtype of type 'CardModel' in type cast
Is there any way to do this properly? My workaround would be to simply "wrap" the Card class inside the CardModel and provide a toCard() method which is not very elegant :S
Freezed doesn’t support inheritance at the moment so it’s recommended to use composition instead of inheritance as mentioned by the creator here:
https://github.com/rrousselGit/freezed/issues/464
And in the comments of the post.