getMessageById method Null safety

Future getMessageById(
  1. {required dynamic type,
  2. required String? messageId}
)

获取本地单条消息 target 聊天对象， JMSingle | JMGroup messageId 本地数据库中的消息id，非 serverMessageId

Implementation

Future<dynamic> getMessageById({
  required dynamic type,

  /// (JMSingle | JMGroup | JMChatRoom)
  required String? messageId,
}) async {
  Map param = type.toJson();

  param
    ..addAll({
      'messageId': messageId,
    });

  Map msgMap = await _channel.invokeMethod(
      'getMessageById', param..removeWhere((key, value) => value == null));

  return JMNormalMessage.generateMessageFromJson(msgMap);
}