import 'package:json_annotation/json_annotation.dart'; part 'base_message.g.dart'; @JsonSerializable() class BaseMessage { @JsonKey(name: 'cmd') String? cmd; @JsonKey(name: 'body') String? data; BaseMessage({this.cmd, this.data}); factory BaseMessage.fromJson(Map json) => _$BaseMessageFromJson(json); Map toJson() => _$BaseMessageToJson(this); }