Clean Architecture for SwiftUI + Combine
A demo project showcasing the setup of the SwiftUI app with Clean Architecture.
The app uses the restcountries.eu REST API to show the list of countries and details about them.
Check out mvvm branch for the MVVM revision of the same app.
For the example of handling the authentication state in the app, you can refer to my other tiny project that harnesses the locks and keys principle for solving this problem.
- Vanilla SwiftUI + Combine implementation
- Decoupled Presentation, Business Logic, and Data Access layers
- Full test coverage, including the UI (thanks to the ViewInspector)
- Redux-like centralized
AppStateas the single source of truth
- Data persistence with CoreData
- Native SwiftUI dependency injection
- Programmatic navigation. Push notifications with deep link
- Simple yet flexible networking layer built on Generics
- Handling of the system events (such as
- Built with SOLID, DRY, KISS, YAGNI in mind
- Designed for scalability. It can be used as a reference for building large production apps
SwiftUI views that contain no business logic and are a function of the state.
Side effects are triggered by the user's actions (such as a tap on a button) or view lifecycle event
onAppear and are forwarded to the
State and business logic layer (
Interactors) are navitely injected into the view hierarchy with
Business Logic Layer
Business Logic Layer is represented by
Interactors receive requests to perform work, such as obtaining data from an external source or making computations, but they never return data back directly.
Instead, they forward the result to the
AppState or to a
Binding. The latter is used when the result of work (the data) is used locally by one View and does not belong to the
Previously, this app did not use CoreData for persistence, and all loaded data were stored in the
With the persistence layer in place we have a choice - either to load the DB content onto the
AppState, or serve the data from
Interactors on an on-demand basis through
The first option suits best when you don't have a lot of data, for example, when you just store the last used login email in the
UserDefaults. Then, the corresponding string value can just be loaded onto the
AppState at launch and updated by the
Interactor when the user changes the input.
The second option is better when you have massive amounts of data and introduce a fully-fledged database for storing it locally.
Data Access Layer
Data Access Layer is represented by
Repositories provide asynchronous API (
Publisher from Combine) for making CRUD operations on the backend or a local database. They don't contain business logic, neither do they mutate the
AppState. Repositories are accessible and used only by the Interactors.