json_extension 0.4.1

Uses class_extensions and json_serializable to generate methods for object serialization from/to json map/string.

Description

Uses class_extensions and json_serializable to generate methods for object serialization from/to json map/string.

See also withers_extension, to_string_extension

Tutorial

1. We need a class to generate json serialization methods for.

   ${PROJECT_ROOT}/lib/model.dart

   import 'package:meta/meta.dart';
      
   @immutable
   class SomeValueClass {
     final String strVal;
     final int intVal;
   }
   

2. For json serialization to work you need to add some boiler plate:

   • import 'dart:convert';
   • part 'model.g.dart';
   • annotation @Json()
   • mixin _$SomeValueClass
   • all args constructor SomeValueClass(this.strVal, this.intVal);
   • factories SomeValueClass.fromJson(Map<String, dynamic> json) and SomeValueClass.fromJsonString(String json)

   ${PROJECT_ROOT}/lib/model.dart

   import 'dart:convert';
      
   import 'package:json_extension_annotations/annotations.dart';
   import 'package:meta/meta.dart';
      
   part 'model.g.dart';
      
   @Json()
   @immutable
   class SomeValueClass with _$SomeValueClass {
     final String strVal;
     final int intVal;
      
     SomeValueClass(this.strVal, this.intVal);
      
     factory SomeValueClass.fromJson(Map<String, dynamic> json) =>
         _$SomeValueClass.fromJson(json);
      
     factory SomeValueClass.fromJsonString(String json) =>
         _$SomeValueClass.fromJsonString(json);
   }
   

3. Configure code generation. More info at build.

   ${PROJECT_ROOT}/build.yaml

   targets:
     $default:
       builders:
         class_extensions:
           generate_for:
           - lib/*.dart
   

4. Add dependencies.

   ${PROJECT_ROOT}/pubspec.yaml

   name: example
      
   dependencies:
     json_extension_annotations: ^0.2.0
      
   dev_dependencies:
     build_runner: ^1.0.0
     json_extension: ^0.2.0
     json_serializable: ^3.2.3
   

5. Run code generation: pub run build_runner build. File ${PROJECT_ROOT}/lib/model.g.dart should be created.

6. If everything goes well you should be able to use json.

   ${PROJECT_ROOT}/bin/main.dart

   import 'package:example/model.dart';
      
   void main() {
     var some = SomeValueClass("some", 0);
      
     var jsonMap = some.toJson();
     var someFromMap = SomeValueClass.fromJson(jsonMap);
      
     var jsonString = some.toJsonString();
     var someFromString = SomeValueClass.fromJsonString(jsonString);
   }
   

7. You can also see the example.