toJson method

Implementation

Map toJson() {
  Map data = {};
  data.putIfNotNull(
      'direction', direction == EMSearchDirection.Up ? "up" : "down");
  data.putIfNotNull('startTs', startTs);
  data.putIfNotNull('endTs', endTs);
  data.putIfNotNull('from', from);
  data.putIfNotNull('needSave', needSave);
  data.putIfNotNull('msgTypes',
      msgTypes?.toSet().map<String>((e) => messageTypeToTypeStr(e)).toList());

  return data;
}