在nullsafety之后对json_serializable使用firestore

import 'package:json_annotation/json_annotation.dart';

@JsonSerializable()
class MyClass {
  @JsonKey(name: 'name')
  String? name;

  @JsonKey(name: 'age')
  int? age;

  MyClass({this.name, this.age});

  factory MyClass.fromJson(Map<String, dynamic> json) =>
      _$MyClassFromJson(json);

  Map<String, dynamic> toJson() => _$MyClassToJson(this);
}

flutter pub run build_runner build

import 'package:cloud_firestore/cloud_firestore.dart';

void saveToFirestore(MyClass obj) {
  FirebaseFirestore.instance
      .collection('my_collection')
      .doc('my_document')
      .set(obj.toJson());
}

import 'package:cloud_firestore/cloud_firestore.dart';

Future<MyClass> getFromFirestore() async {
  DocumentSnapshot snapshot = await FirebaseFirestore.instance
      .collection('my_collection')
      .doc('my_document')
      .get();
  Map<String, dynamic> data = snapshot.data() as Map<String, dynamic>;
  return MyClass.fromJson(data);
}