Dart json serialization, how to deal with _id from mongodb being private in Dart?

Question

I'm using automatic serialization/deserialization in dart like mentioned here

import 'package:json_annotation/json_annotation.dart';

part 'billing.g.dart';

@JsonSerializable()
class Billing {
  Billing(){}
  String _id;
  String name;
  String status;
  double value;
  String expiration;
  factory Billing.fromJson(Map<String, dynamic> json) => _$BillingFromJson(json);
  Map<String, dynamic> toJson() => _$BillingToJson(this);
}

But in order for the serialization/deserialization to work, the fields must be public. However, in Dart, a field with _ at the beggining is private. So I can't use _id from mongodb to serialize/deserialize things.

How can I overcome this?

Solution

You can use @JsonKey annotation. Refer https://pub.dev/documentation/json_annotation/latest/json_annotation/JsonKey/name.html

import 'package:json_annotation/json_annotation.dart';

part 'billing.g.dart';

@JsonSerializable()
class Billing {
  Billing(){}

  // Tell json_serializable that "_id" should be
  // mapped to this property.
  @JsonKey(name: '_id')
  String id;
  String name;
  String status;
  double value;
  String expiration;
  factory Billing.fromJson(Map<String, dynamic> json) => _$BillingFromJson(json);
  Map<String, dynamic> toJson() => _$BillingToJson(this);
}