auto_data 0.0.3

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  • Changelog
  • Example
  • Installing
  • 77

auto_data #

Generate simple data classes for Dart.

A data class is an immutable class meant to hold data, similar to Kotlin's data class.

Example #

Specify the data class using the @data annotation:

class $Point {
  double x;
  double y;

Enjoy your generated named constructor, ==/hashCode, toString, copyWith, and serialization:

class Point {
  final double x;
  final double y;

  const Point({
    @required this.x,
    @required this.y,

  bool operator ==(Object other) =>
      identical(this, other) ||
      other is Point &&
          runtimeType == other.runtimeType &&
          x == other.x &&
          y == other.y;

  int get hashCode => x.hashCode ^ y.hashCode;

  String toString() {
    return 'Point{x: ' + x.toString() + ', y: ' + y.toString() + '}';

  Point copyWith({
    double x,
    double y,
  }) {
    return Point(
      x: x ?? this.x,
      y: y ?? this.y,

  Point.fromMap(Map<String, dynamic> m)
      : x = m['x'],
        y = m['y'];

  Map<String, dynamic> toMap() => {'x': x, 'y': y};

  factory Point.fromJson(String json) => Point.fromMap(jsonDecode(json));

  String toJson() => jsonEncode(toMap());

Requirements #

Add the following to your pubspec.yaml:

  auto_data: ^0.0.3

  build_runner: ^1.0.0
  auto_data_generator: ^0.0.3

Create your point.dart file with correct imports:

import 'package:meta/meta.dart';
import 'package:collection/collection.dart';
import 'package:auto_data/auto_data.dart';
import 'dart:convert';

part 'point.g.dart';

class $Point {
  double x;
  double y;

Lastly, generate using build_runner:

pub run build_runner build


pub run build_runner watch

Use your generated Point class:

import 'point.dart';

final p1 = Point(x: 0, y: 1);
final p2 = Point(x: 0, y: 2);
assert(p1 != p2);
final p3 = p1.copyWith(y: 2);
assert(p2 == p3);

Advanced usage #

import 'package:collection/collection.dart';
import 'package:meta/meta.dart';
import 'package:auto_data/auto_data.dart';
import 'dart:convert';
import 'foo.dart';

part 'person.g.dart';

/// All comments are copied to generated code
class $Person {
  /// This field gets a default value
  String name = 'Paul';

  /// This field is not required
  double weight;

  /// Age of the person
  int age;

  /// Depend on another generated class
  $Foo foo;

  /// Deep comparison of lists
  List<$Person> friends;

  /// Custom constructors are copied over
  : name = 'Albert',
    age = 140;

Todo's #

  • [ ] Optional constructor types (named, private, const, etc)
  • [x] Custom constructors should be copied over (Issue #1)
  • [x] Default values by assigning during declaration: String name = 'Paul';
  • [x] Add @nullable annotation for fields that are not required
  • [ ] Deep immutability for Map
  • [x] Deep immutability for List
  • [x] Serialization toMap/fromMap
  • [x] Serialization toJson/fromJson

Limitations #

Cannot set values to null with copyWith #

Ex) Clearing a user's avatar image:

profile = profile.copyWith(imageUrl: null); // This won't have an effect since copyWith ignores null input parameters.

References #

  1. Issue: Statically tracked shared immutable objects
  2. Proposal: Shared immutable objects
  3. Patterns and related features

0.0.3 #

  • Added support for toJson and fromJson
  • Renamed toFirebaseMap/fromFirebaseMap -> toMap/fromMap

0.0.2 #

  • Various package structure fixes

[0.0.1] - July 24, 2019.

  • Initial release.


import 'package:example/foo.dart';
import 'bar.dart';

void main() {
  final foo = new Foo();
  final bar = new Bar(foo: foo);

Use this package as a library

1. Depend on it

Add this to your package's pubspec.yaml file:

  auto_data: ^0.0.3

2. Install it

You can install packages from the command line:

with pub:

$ pub get

with Flutter:

$ flutter pub get

Alternatively, your editor might support pub get or flutter pub get. Check the docs for your editor to learn more.

3. Import it

Now in your Dart code, you can use:

import 'package:auto_data/auto_data.dart';
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Learn more about scoring.

We analyzed this package on Jan 19, 2020, and provided a score, details, and suggestions below. Analysis was completed with status completed using:

  • Dart: 2.7.0
  • pana: 0.13.4

Health suggestions

Fix lib/src/annotations.dart. (-1 points)

Analysis of lib/src/annotations.dart reported 2 hints:

line 15 col 19: Avoid const keyword.

line 25 col 27: Avoid const keyword.

Maintenance suggestions

Package is pre-v0.1 release. (-10 points)

While nothing is inherently wrong with versions of 0.0.*, it might mean that the author is still experimenting with the general direction of the API.


Package Constraint Resolved Available
Direct dependencies
Dart SDK >=2.1.0 <3.0.0
Dev dependencies
test any