b.dev/packages/freezed

 When you have a data class in Flutter, like a User class with a name and age, you often need to write a lot of extra stuff. You have to create a copyWith method, override the == operator, and a hashCode getter. All this is just to make the class work correctly for state management. It's a pain.

normal class looks:

class User {

  final String name;

  final int age;

  User({required this.name, required this.age});

  User copyWith({String? name, int? age}) {

    return User(

      name: name ?? this.name,

      age: age ?? this.age,

    );

  }

  // .. and the == and hashCode overrides you saw before

}

ow, check out how the freezed package does it using freezed:

import 'package:freezed_annotation/freezed_annotation.dart';

part 'user.freezed.dart';

@freezed

class User with _$User {

  const factory User({required String name, required int age}) = _User;

}

that's it. It's magic!