Template: Clean Architecture Feature

The canonical end-to-end feature: all three layers, DI, error handling, and tests. This bundle ships representative .swift files you can copy and rename. See architecture/clean_architecture.md.

Folder Structure

clean_architecture_feature/
├── Domain.swift          // entity + repository protocol + use case + DomainError
├── Data.swift            // DTO + mapper + repository implementation
├── Presentation.swift    // ViewState + ViewModel + View
├── CompositionRoot.swift // wires the graph (prod + preview/test)
└── Tests.swift           // use case + ViewModel + mapper tests

The files use a sample Article feature. Replace Article/article with your entity, and split each file into per-type files when you copy it into a real module.

How the layers connect

ArticlesView → ArticlesViewModel → FetchArticlesUseCase → ArticleRepository (protocol)
                                                              ▲
                                          RemoteArticleRepository (Data) ── APIClient

Conventions Demonstrated

• Domain is framework-free; repository protocol + use case live here.
• Data maps ArticleDTO → Article and NetworkError → DomainError; DTOs never leak.
• Presentation uses a single ViewState enum and an @Observable @MainActor ViewModel.
• DI through a composition root with a #if DEBUG preview/test factory.
• Tests are deterministic with simple stubs (no real network).

Usage

1. Copy the bundle into your feature module.
2. Rename Article/article → your entity.
3. Split combined files into one-type-per-file.
4. Point RemoteArticleRepository at your endpoint.
5. Run the tests; extend coverage for your business rules.

See also: feature_module, repository_layer, swiftui_screen, unit_test_template.