swiftui-component

name	swiftui-component
description	Creates SwiftUI views and screens following MVVM with thin view layers, ViewModel extraction, previews, accessibility support, and loading/error states. Use when user says "create a SwiftUI view", "build a screen", "add a new view", "create a component", "build the UI for", "add a SwiftUI screen", or "make a new SwiftUI page".
metadata	{"author":"swift-unit-test-instructions","version":"1.0.0","category":"swift"}

SwiftUI Component Creator

Instructions

Step 1: Clarify Requirements

Ask if not already provided:

• What does the view display? (list, detail, form, modal, etc.)
• What user interactions does it support? (tap, swipe, input, navigation)
• What data does it need? (local state, fetched from API, passed in)
• Any navigation behavior? (NavigationLink, sheet, fullScreenCover)
• Min iOS version? (affects @Observable vs ObservableObject)

Step 2: Choose the State Pattern

iOS Target	Pattern
iOS 17+	@Observable macro on ViewModel, @State private var viewModel in View
iOS 16 and below	ObservableObject + @Published, @StateObject in View

Step 3: Generate the Files

Always generate two files: one View, one ViewModel.

View template (iOS 17+ / @Observable):

// Features/[Name]/[Name]View.swift
import SwiftUI

struct [Name]View: View {
    @State private var viewModel: [Name]ViewModel

    init(viewModel: [Name]ViewModel = [Name]ViewModel()) {
        _viewModel = State(initialValue: viewModel)
    }

    var body: some View {
        content
            .task { await viewModel.onAppear() }
            .alert("Error", isPresented: .constant(viewModel.error != nil)) {
                Button("OK") { viewModel.dismissError() }
            } message: {
                Text(viewModel.error?.localizedDescription ?? "")
            }
    }

    @ViewBuilder
    private var content: some View {
        if viewModel.isLoading {
            ProgressView()
        } else {
            mainContent
        }
    }

    private var mainContent: some View {
        // Primary UI here
        Text(viewModel.title)
            .accessibilityLabel(viewModel.title)
    }
}

#Preview {
    [Name]View(viewModel: [Name]ViewModel())
}

View template (iOS 16 / ObservableObject):

// Features/[Name]/[Name]View.swift
import SwiftUI

struct [Name]View: View {
    @StateObject private var viewModel: [Name]ViewModel

    init(viewModel: [Name]ViewModel = [Name]ViewModel()) {
        _viewModel = StateObject(wrappedValue: viewModel)
    }

    var body: some View {
        // same structure as above
    }
}

ViewModel template (iOS 17+ / @Observable):

// Features/[Name]/[Name]ViewModel.swift
import Foundation
import Observation

@MainActor
@Observable
final class [Name]ViewModel {
    // MARK: - Output State
    private(set) var isLoading = false
    private(set) var title: String = ""
    private(set) var error: Error?

    // MARK: - Dependencies
    private let service: [Service]Protocol

    init(service: [Service]Protocol = [Service]()) {
        self.service = service
    }

    // MARK: - Actions
    func onAppear() async {
        isLoading = true
        defer { isLoading = false }
        do {
            title = try await service.fetchTitle()
        } catch {
            self.error = error
        }
    }

    func dismissError() {
        error = nil
    }
}

ViewModel template (iOS 16 / ObservableObject):

// Features/[Name]/[Name]ViewModel.swift
import Foundation

@MainActor
final class [Name]ViewModel: ObservableObject {
    @Published private(set) var isLoading = false
    @Published private(set) var title: String = ""
    @Published private(set) var error: Error?

    private let service: [Service]Protocol

    init(service: [Service]Protocol = [Service]()) {
        self.service = service
    }

    func onAppear() async {
        isLoading = true
        defer { isLoading = false }
        do {
            title = try await service.fetchTitle()
        } catch {
            self.error = error
        }
    }

    func dismissError() {
        error = nil
    }
}

Step 4: Quality Checklist

Before finalizing, verify:

• View has zero business logic — only layout and presentation
• ViewModel has no import SwiftUI (only Foundation, Observation)
• All external dependencies are injected via init
• #Preview compiles with default / mock data
• Loading state is handled
• Error state is handled (alert, inline message, or empty state)
• Interactive elements have .accessibilityLabel where needed
• Navigation is handled via ViewModel output flags, not inline logic

Step 5: Sub-View Extraction

If the view body grows complex (>50 lines), extract sub-views:

// Inline private sub-view (same file — preferred for small extractions)
private extension [Name]View {
    var headerSection: some View {
        VStack(alignment: .leading) {
            // ...
        }
    }
}

For reusable components, create a separate file in Core/Components/.

Examples

Example 1: List screen

User says: "Create a SwiftUI product list screen that fetches products and shows a loading spinner"

Files generated:

• ProductListView.swift — list with .task, loading overlay, error alert
• ProductListViewModel.swift — fetches from ProductRepositoryProtocol, manages loading/error state

Example 2: Detail screen

User says: "Build a profile detail screen showing user name, avatar, bio, and a logout button"

Files generated:

• ProfileView.swift — avatar (AsyncImage), name, bio, logout button
• ProfileViewModel.swift — onLogout() action, user state, logout confirmation flag

Example 3: Form / input screen

User says: "Create a settings screen with a toggle for notifications and a text field for display name"

Files generated:

• SettingsView.swift — Form with Toggle and TextField bound to ViewModel
• SettingsViewModel.swift — notificationsEnabled, displayName, save() async action

Troubleshooting

Preview crashes: ViewModel has a real dependency with side effects. Add a static var preview: [Name]ViewModel with a mock service, or make the default init safe for previews.

View body is growing too large: Extract into private @ViewBuilder computed properties or private extension sub-views. If a sub-view needs significant logic, give it its own ViewModel.

State not updating in view: For @Observable, ensure @State is used in the View (not @StateObject). For ObservableObject, ensure @Published is on the property.