import 'package:json_annotation/json_annotation.dart'; import 'package:model/model.dart'; class AvatarIdNullableConverter implements JsonConverter { const AvatarIdNullableConverter(); @override AvatarId? fromJson(String? json) => json != null ? AvatarId(json) : AvatarId.initial(); @override String? toJson(AvatarId? object) => object?.id; }