swiftui-architecture

Extract logic from SwiftUI views by moving state and business logic into a ViewModel (MVVM) or Store (TCA). This separation keeps views focused on UI rendering and improves testability by isolating logic for unit testing without view dependencies.

MVVM centralizes state in a ViewModel class; TCA uses a unidirectional architecture with explicit state, actions, and effects; native SwiftUI relies on @State and @ObservedObject. Each trades complexity for predictability—MVVM is familiar, TCA scales large apps, native SwiftUI minimizes boilerplate for simple features.

Refactor by extracting view logic into a separate observable object or reducer, injecting dependencies, and replacing direct state mutations with explicit action handlers. This decouples view rendering from business logic, enabling isolated unit tests without UI frameworks.

Yes. The Coordinator pattern manages navigation and view lifecycle in SwiftUI by centralizing navigation logic outside views. It pairs well with MVVM or TCA to coordinate multiple screens and handle deep linking while keeping views stateless.

Use @State for local view state, @ObservedObject for external observable models, @EnvironmentObject for app-wide shared state, and @Binding for two-way connections. Choosing correctly prevents unnecessary re-renders and keeps state flow explicit and testable.

Avoid inline logic when code needs unit testing, reuse across multiple views, or depends on external APIs and database calls. Direct view logic couples rendering to side effects, making tests slow and brittle; extraction enables fast, focused tests.