example/example.md

cobalt_annotations example #

Annotations only — they carry no runtime. The generator in cobalt_generator reads them, and cobalt_lint checks them in the IDE.

import 'package:cobalt/cobalt.dart';

part 'notes.g.dart';

@cobaltInit
class Database implements AsyncInitializable {
  Database();

  @override
  Future<void> init() async { /* open the file */ }
}

@CobaltInject(exposeAs: NoteStore)
class NoteRepository implements NoteStore {
  NoteRepository(this.database);
  final Database database;
}

@CobaltInit(dependsOn: [Database])
class SearchIndex implements AsyncInitializable {
  SearchIndex(this.database);
  final Database database;

  @override
  Future<void> init() async { /* build the index */ }
}

@cobaltInject
class NoteEditor {
  NoteEditor(this.store, {@cobaltParam required this.id});

  final NoteStore store;
  final int id;
}

@cobaltTransient
class NotesController with _$NotesController {
  NotesController();

  @injected
  late final NoteStore _store;
}

A full application using every annotation lives in examples/notes_app.

SearchIndex may state dependsOn: [Database] only because Database is @CobaltInit too. dependsOn sequences phase 1, so it can wait for an async registration and nothing else; naming a plain one fails the build.

NoteEditor takes an @cobaltParam, so it is registered as a parameterized factory and the generator writes typedef $NoteEditorArgs = ({int id}); beside the container. Resolve it with getWithParam<NoteEditor, $NoteEditorArgs>((id: 7)) — the store still comes from the graph.