swiftui-expert

Use the @Observable macro on a class instead of ObservableObject with @Published. Views then hold the model with @State, and only properties actually read inside body trigger updates, removing the need for @StateObject and @ObservedObject.

@State means the view owns the value, @Binding lets a view mutate a value owned by a parent, and @Environment reads a value injected higher in the view hierarchy. @Bindable creates bindings from an @Observable model passed via parameters or environment.

Use NavigationStack or NavigationSplitView. NavigationView is deprecated in iOS 16 and later, so new code targeting modern iOS versions should adopt the stack-based navigation APIs.

This happens when ForEach uses indices or lacks stable identity. Make your model conform to Identifiable and iterate directly over the collection so SwiftUI can track item identity across insertions and deletions.

Use LazyVStack inside ScrollViews for large lists so views are created on demand. For fewer than about 20 items, a normal VStack is faster because it pre-calculates layout boundaries instantly.

Not always. SwiftUI treats the view as a function of state, so views can own local @State and pass @Bindings down. Reserve full view models for complex orchestration that spans multiple views.