swiftui-view-refactor

# SwiftUI View Refactor _Attribution: copied from @Dimillian’s `Dimillian/Skills` (2025-12-31)._ ## Overview Apply a consistent structure and dependency pattern to SwiftUI views, with a focus on ordering, Model-View (MV) patterns, careful view model handling, and correct Observation usage. ## Core Guidelines ### 1) View ordering (top → bottom) - Environment - `private`/`public` `let` - `@State` / other stored properties - computed `var` (non-view) - `init` - `body` - computed view builders / other view helpers - helper / async functions ### 2) Prefer MV (Model-View) patterns - Default to MV: Views are lightweight state expressions; models/services own business logic. - Favor `@State`, `@Environment`, `@Query`, and `task`/`onChange` for orchestration. - Inject services and shared models via `@Environment`; keep views small and composable. - Split large views into subviews rather than introducing a view model. ### 3) Split large bodies and view properties - If `body` grows beyond a screen or has multiple logical sections, split it into smaller subviews. - Extract large computed view properties (`var header: some View { ... }`) into dedicated `View` types when they carry state or complex branching. - It's fine to keep related subviews as computed view properties in the same file; extract to a standalone `View` struct only when it structurally makes sense or when reuse is intended. - Prefer passing small inputs (data, bindings, callbacks) over reusing the entire parent view state. Example (extracting a section): ```swift var body: some View { VStack(alignment: .leading, spacing: 16) { HeaderSection(title: title, isPinned: isPinned) DetailsSection(details: details) ActionsSection(onSave: onSave, onCancel: onCancel) } } ``` Example (long body → shorter body + computed views in the same file): ```swift var body: some View { List { header filters results footer } } private var header: some View { VStack(alignment: .leading, spacing: 6) { Text(title).font(.title2) Text(subtitle).font(.subheadline) } } private var filters: some View { ScrollView(.horizontal, showsIndicators: false) { HStack { ForEach(filterOptions, id: \.self) { option in FilterChip(option: option, isSelected: option == selectedFilter) .onTapGesture { selectedFilter = option } } } } } ``` Example (extracting a complex computed view): ```swift private var header: some View { HeaderSection(title: title, subtitle: subtitle, status: status) } private struct HeaderSection: View { let title: String let subtitle: String? let status: Status var body: some View { VStack(alignment: .leading, spacing: 4) { Text(title).font(.headline) if let subtitle { Text(subtitle).font(.subheadline) } StatusBadge(status: status) } } } ``` ### 4) View model handling (only if already present) - Do not introduce a view model unless the request or existing code clearly calls for one. - If a view model exists, make it non-optional when possible. - Pass dependencies to the view via `init`, then pass them into the view model in the view's `init`. - Avoid `bootstrapIfNeeded` patterns. Example (Observation-based): ```swift @State private var viewModel: SomeViewModel init(dependency: Dependency) { _viewModel = State(initialValue: SomeViewModel(dependency: dependency)) } ``` ### 5) Observation usage - For `@Observable` reference types, store them as `@State` in the root view. - Pass observables down explicitly as needed; avoid optional state unless required. ## Workflow 1) Reorder the view to match the ordering rules. 2) Favor MV: move lightweight orchestration into the view using `@State`, `@Environment`, `@Query`, `task`, and `onChange`. 3) If a view model exists, replace optional view models with a non-optional `@State` view model initialized in `init` by passing dependencies from the view. 4) Confirm Observation usage: `@State` for root `@Observable` view models, no redundant wrappers. 5) Keep behavior intact: do not change layout or business logic unless requested. ## Notes - Prefer small, explicit helpers over large conditional blocks. - Keep computed view builders below `body` and non-view computed vars above `init`. - For MV-first guidance and rationale, see `references/mv-patterns.md`.