SWIFTUI DETAIL SCREEN

ARCHITECTURE: Protocol-Oriented with ObservedObject

protocol ProductDisplay {
  var id: String { get }
  var title: String { get }
  var price: Decimal { get }
  var images: [URL] { get }
}

class ProductViewModel: ObservableObject {
  @Published var product: ProductDisplay?
  @Published var isLoading = false
  @Published var error: Error?
  
  func load(productId: String) async {
    isLoading = true
    do {
      product = try await fetchProduct(productId)
    } catch {
      self.error = error
    }
    isLoading = false
  }
}

struct ProductDetailView: View {
  @StateObject var viewModel = ProductViewModel()
  
  var body: some View {
    if let product = viewModel.product {
      VStack(spacing: 16) {
        AsyncImage(url: product.images.first)
        Text(product.title).font(.headline)
        Text("$" + String(product.price)).font(.title2)
      }
    } else if viewModel.isLoading {
      ProgressView()
    } else if let error = viewModel.error {
      ErrorView(error: error)
    }
  }
}

STATE MANAGEMENT

Data binding: ViewState drives UI refresh
Async/await: Load product on appear
Error handling: Shows error overlay
Actor isolation: Thread-safe data fetching