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