swiftui-patterns

# SwiftUI Patterns Modern SwiftUI patterns for building declarative, performant user interfaces on Apple platforms. Covers the Observation framework, view composition, type-safe navigation, and performance optimization. ## When to Activate - Building SwiftUI views and managing state (`@State`, `@Observable`, `@Binding`) - Designing navigation flows with `NavigationStack` - Structuring view models and data flow - Optimizing rendering performance for lists and complex layouts - Working with environment values and dependency injection in SwiftUI ## State Management ### Property Wrapper Selection Choose the simplest wrapper that fits: | Wrapper | Use Case | |---------|----------| | `@State` | View-local value types (toggles, form fields, sheet presentation) | | `@Binding` | Two-way reference to parent's `@State` | | `@Observable` class + `@State` | Owned model with multiple properties | | `@Observable` class (no wrapper) | Read-only reference passed from parent | | `@Bindable` | Two-way binding to an `@Observable` property | | `@Environment` | Shared dependencies injected via `.environment()` | ### @Observable ViewModel Use `@Observable` (not `ObservableObject`) — it tracks property-level changes so SwiftUI only re-renders views that read the changed property: ```swift @Observable final class ItemListViewModel { private(set) var items: [Item] = [] private(set) var isLoading = false var searchText = "" private let repository: any ItemRepository init...