json_serializable 0.5.8+1
json_serializable: ^0.5.8+1 copied to clipboard


Generates utilities to aid in serializing to/from JSON.

Build Status

Provides Dart Build System builders for handling JSON.

The builders generate code when they find members annotated with classes defined in package:json_annotation.

  • To generate to/from JSON code for a class, annotate it with JsonSerializable. You can provide arguments to JsonSerializable to configure the generated code. You can also customize individual fields by annotating them with JsonKey and providing custom arguments.

  • To generate a Dart field with the contents of a file containting JSON, use the JsonLiteral annotation.

To configure your project for the latest released version of, json_serializable see the example.

Example #

Given a library example.dart with an Person class annotated with @JsonSerializable():

import 'package:json_annotation/json_annotation.dart';

part 'example.g.dart';

@JsonSerializable(nullable: false)
class Person extends Object with _$PersonSerializerMixin {
  final String firstName;
  final String lastName;
  final DateTime dateOfBirth;
  Person({this.firstName, this.lastName, this.dateOfBirth});
  factory Person.fromJson(Map<String, dynamic> json) => _$PersonFromJson(json);

Building creates the corresponding part example.g.dart:

part of 'example.dart';

Person _$PersonFromJson(Map<String, dynamic> json) {
  return new Person(
      firstName: json['firstName'] as String,
      lastName: json['lastName'] as String,
      dateOfBirth: DateTime.parse(json['dateOfBirth'] as String));

abstract class _$PersonSerializerMixin {
  String get firstName;
  String get lastName;
  DateTime get dateOfBirth;
  Map<String, dynamic> toJson() => <String, dynamic>{
        'firstName': firstName,
        'lastName': lastName,
        'dateOfBirth': dateOfBirth.toIso8601String()

Build configuration #

Besides setting arguments on the associated annotation classes, you can also configure code generation by setting values in build.yaml.

          # Specifies a string to add to the top of every generated file.
          # If not specified, the default is the value of `defaultFileHeader`
          # defined in `package:source_gen/source_gen.dart`.
          # Note: use `|` to define a multi-line block.
          header: |
           // Copyright (c) 2018, the Dart project authors.


          # Options configure how source code is generated for every
          # `@JsonSerializable`-annotated class in the package.
          # The default value for each of them: `false`.
          # For usage information, reference the corresponding field in
          # `JsonSerializableGenerator`.
          use_wrappers: true
          any_map: true
          checked: true
          explicit_to_json: true
          generate_to_json_function: true