Master SwiftUI ViewBuilder for Efficient UI Development

Provides expert guidance on SwiftUI ViewBuilder patterns, view composition, and architecture - covering how ViewBuilder works as a result builder, reusable generic components, performance optimization, and state management integration.

Use this skill when writing custom @ViewBuilder functions for conditional content, building generic reusable view components (cards, list rows, form sections), optimizing a view hierarchy to minimize unnecessary rebuilds, implementing lazy loading for large lists, or structuring async loading/error/loaded states in a SwiftUI view. Not a fit for UIKit view composition or for SwiftUI data flow topics unrelated to view building (e.g. networking or persistence).

Explains ViewBuilder as a result builder that transforms multiple view declarations into a single hierarchy, the View protocol's body requirement, and ViewBuilder's automatic type erasure that lets different view types compose seamlessly - illustrated with a conditional-content function returning either a Text or a VStack based on a condition.

Provides a custom generic cardContainer ViewBuilder function accepting a title and @ViewBuilder content closure, styled with padding, background, corner radius, and shadow, plus a generic ListRow struct with Leading/Trailing view type parameters and default EmptyView() closures for optional leading/trailing content.

Performance guidance includes an OptimizedListView example splitting a List into computed @ViewBuilder properties (searchSection, itemsSection) to minimize rebuild scope, and a generic lazyContent function using LazyVStack with an onAppear-triggered pagination callback for large item sets.

State management integration is shown via a DynamicForm view backed by an ObservableObject FormViewModel (@Published fields, a validate() method), with the form body split into inputSection and actionSection ViewBuilder properties. Error handling guidance provides an asyncContent function switching over a LoadingState enum (idle, loading, loaded, error) to render the appropriate content, loading, or error view.

Best practices cover breaking down complex views into computed properties and separate ViewBuilder functions, letting Swift infer return types, using Group/Section without adding unnecessary containers, preferring opacity modifiers over conditional ViewBuilder for performance-critical animations, composing over inheritance, and using preview providers to test ViewBuilder functions across states.

Built entirely on SwiftUI's View protocol, @ViewBuilder result builder, ObservableObject/@Published/@StateObject, and LazyVStack - no external libraries required.

iOS/SwiftUI developers building reusable, composable view components who need concrete generic ViewBuilder patterns and performance guidance rather than a basic SwiftUI syntax introduction.

@ViewBuilder
func cardContainer<Content: View>(
    title: String,
    @ViewBuilder content: () -> Content
) -> some View {