toJson method
转换为基本数据类型的Map。转换结果可以直接使用jsonEncode进行序列化,可以直接保存到mongo数据库
Implementation
@override
Map<String, dynamic> toJson() {
final map = <String, dynamic>{};
if ($projection != null) {
map['\$projection'] = {for (var element in $projection!) element._name: element._value$projection ?? DBUnsupportNullValue('\$projection', element._name)};
}
return map;
}