import 'package:fcm/model/fcm_token.dart'; import 'package:json_annotation/json_annotation.dart'; class FcmTokenNullableConverter implements JsonConverter { const FcmTokenNullableConverter(); @override FcmToken? fromJson(String? json) => json != null ? FcmToken(json) : null; @override String? toJson(FcmToken? object) => object?.value; }