swiftui-view-refactor

SwiftUI View Refactor 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):

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):

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):

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):

@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 Reorder the view to match the ordering rules. Favor MV: move lightweight orchestration into the view using @State, @Environment, @Query, task, and onChange. 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. Confirm Observation usage: @State for root @Observable view models, no redundant wrappers. 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. Large-view handling When a SwiftUI view file exceeds ~300 lines, split it using extensions to group related helpers. Move async functions and helper functions into dedicated private extensions, separated with // MARK: - comments that describe their purpose (e.g., // MARK: - Actions, // MARK: - Subviews, // MARK: - Helpers). Keep the main struct focused on stored properties, init, and body, with view-building computed vars also grouped via marks when the file is long.