auto_json_converter 2.0.1

Provides annotations and builders to generate JsonConverters for types that support toJson and fromJson methods.

Generates JsonConverter<T, Map<String, dynamic>> classes for types that implement fromJson and toJson methods.

Set-up

First follow the setup steps for the json_serializable package.

Then the following dependencies to your pubspec.yaml:

dependencies:
  auto_json_converter_annotations: ^1.0.0

dev_dependencies:
  auto_json_converter: ^2.0.0

Usage

Add the @AutoJsonConverter() annotation from auto_json_converter_annotations to a class that implements fromJson and toJson:

import 'package:auto_json_converter/auto_json_converter.dart';
import 'package:json_annotation/json_annotation.dart';

part 'auto_json_converter_example.g.dart';

@JsonSerializable()
@AutoJsonConverter()
class Example {
  String name;

  Example(this.name);

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

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

You can then run the build_runner via dart run build_runner to generate the converters.

You can then use the generated converter however you'd like. For example to work around generic constraint limitations:

import 'dart:convert';
import 'dart:io';

import 'package:json_annotation/json_annotation.dart';

class Storage<T> {
  File file;
  JsonConverter<T, Map<String, dynamic>> converter;

  Storage({required this.converter, required String location})
    : file = File(location);

  Future<T> load() async {
    var fileContents = await file.readAsString();

    var someDecodedJson = jsonDecode(fileContents);

    var object = converter.fromJson(someDecodedJson);

    return object;
  }

  Future save(T object) async {
    var json = converter.toJson(object);

    var jsonString = jsonEncode(json);

    await file.writeAsString(jsonString);
  }
}

Which would then allow you to do:

void main() async {
  var exampleStorage = Storage<Example>(
    converter: ExampleConverter(),
    location: 'ExampleFile.Json',
  );

  var example = Example('test');

  try {
    example = await exampleStorage.load();
  } catch (_) {}

  example.name = 'new name';

  await exampleStorage.save(example);
}