Swift Expert

Swift and SwiftUI expertise for Leavn app.

Binding Fixes

Problem: $viewModel.property errors Fix: Add @Bindable wrapper in View:

@Bindable var viewModel: MyViewModel

Actor Isolation (Swift 6)

• @MainActor for UI-touching code
• nonisolated for pure functions
• Task { @MainActor in } for async UI updates
• Never access @MainActor properties in deinit

@Observable Migration

Old: @Published var x + ObservableObject New: @Observable class + plain var x View: @State var vm = ViewModel() (not @StateObject)

SwiftUI Anti-Patterns

• Heavy computation in View body → Extract to ViewModel
• @State for reference types → Use @StateObject/@State with @Observable
• Missing @MainActor on ViewModels → Add it
• Force unwrapping in Views → Use nil coalescing

Common Compiler Errors

• “Cannot convert” → Check Optional unwrapping
• “Actor-isolated” → Add @MainActor or nonisolated
• “Missing conformance” → Add protocol or use type erasure
• “Ambiguous” → Add explicit type annotation

Use when: Swift errors, SwiftUI bugs, migration issues, best practices