view_model_generator

Generate ViewModelSpec code from annotations for view_model.

Idea

You write a ViewModel class, the generator writes the spec for you.

final counterSpec = ViewModelSpec<CounterViewModel>(
  builder: () => CounterViewModel(),
);

@GenSpec
class CounterViewModel extends ViewModel {}

Installation

dev_dependencies:
  view_model_generator: ^15.0.0-dev.3
  build_runner: ^2.7.1

dependencies:
  view_model_annotation: ^15.0.0-dev.3

Basic Flow

import 'package:view_model/view_model.dart';
import 'package:view_model_annotation/view_model_annotation.dart';

part 'my_view_model.vm.dart';

@GenSpec
class MyViewModel extends ViewModel {
  MyViewModel();
}

dart run build_runner build

Naming

The spec variable name is derived from the class name:

• UserViewModel -> userSpec
• CartStore -> cartStoreSpec

Arguments

Required constructor parameters become arg, arg2, arg3, or arg4.

@GenSpec
class UserViewModel extends ViewModel {
  final int userId;
  final Repository repo;

  UserViewModel(this.userId, this.repo);
}

final vm = viewModelBinding.watch(userSpec(123, repository));

Rules:

• Up to 4 required parameters are supported
• If factory spec(...) exists, it is used instead of the constructor
• For spec(...), required and optional parameters are included

Keep Alive

@GenSpec(aliveForever: true, key: 'AuthGlobal')
class AuthViewModel extends ViewModel {}

If the spec has arguments, aliveForever is generated as a closure.

Key and Tag

Use raw string templates to emit interpolation:

@GenSpec(key: r'${p.id}', tag: r'${p.name}')
class ProfileViewModel extends ViewModel {
  final Profile p;

  ProfileViewModel(this.p);
}

Use Expression for non-string expressions:

@GenSpec(key: Expression('repo'), tag: Expression('repo.id'))
class RepoViewModel extends ViewModel {
  final Repository repo;

  RepoViewModel(this.repo);
}

Custom Factory

@GenSpec
class SettingsViewModel extends ViewModel {
  final bool isDark;

  SettingsViewModel({this.isDark = false});

  factory SettingsViewModel.spec({required bool isDark}) {
    return SettingsViewModel(isDark: isDark);
  }
}

Notes

• Classes without an unnamed constructor or spec factory are skipped