Composition root

UseCases is the only type that constructs NoteRepositoryImpl.

clean-architectureserverpodfeature-first

lib/src/app/ stays outside the feature. Feature-first does not mean the endpoint constructs the repository. UseCases still does, so a test can build SaveNoteUseCase without the feature's infra.

Repositories holds the store and returns NoteRepositoryImpl(store). UseCases holds the repositories, the clock, and the id generator, and returns a SaveNoteUseCase or a ListNotesUseCase.

dart

SaveNoteUseCase saveNote() => SaveNoteUseCase(
  _repositories.noteRepository(),
  clock: _clock,
  ids: _ids,
);

The endpoint calls useCases.saveNote(). A unit test does not. It constructs SaveNoteUseCase with a fake repository, which is why the use case depends on the port.

app/ has no title check and no SQL. Those stay in Note.create and the repository impl. The files are lib/src/app/use_cases.dart and lib/src/app/repositories.dart.

Next: Tests.