swiftui-view-refactor

SwiftUI View Refactor

Overview

Refactor SwiftUI views toward small, explicit, stable view types. Default to vanilla SwiftUI: local state in the view, shared dependencies in the environment, business logic in services/models, and view models only when the request or existing code clearly requires one.

Core Guidelines

1) View ordering (top → bottom)

• Enforce this ordering unless the existing file has a stronger local convention you must preserve.
• Environment
• private/public let
• @State / other stored properties
• computed var (non-view)
• init
• body
• computed view builders / other view helpers
• helper / async functions

2) Default to MV, not MVVM

• Views should be lightweight state expressions and orchestration points, not containers for business logic.
• Favor @State, @Environment, @Query, .task, .task(id:), and onChange before reaching for a view model.
• Inject services and shared models via @Environment; keep domain logic in services/models, not in the view body.
• Do not introduce a view model just to mirror local view state or wrap environment dependencies.
• If a screen is getting large, split the UI into subviews before inventing a new view model layer.

3) Strongly prefer dedicated subview types over computed some View helpers

• Flag body properties that are longer than roughly one screen or contain multiple logical sections.
• Prefer extracting dedicated View types for non-trivial sections, especially when they have state, async work, branching, or deserve their own preview.
• Keep computed some View helpers rare and small. Do not build an entire screen out of private var header: some View-style fragments.
• Pass small, explicit inputs (data, bindings, callbacks) into extracted subviews instead of handing down the entire parent state.
• If an extracted subview becomes reusable or independently meaningful, move it to its own file.

Prefer:

var body: some View {
    List {
        HeaderSection

Avoid:

3b) Extract actions and side effects out of body

• Do not keep non-trivial button actions inline in the view body.
• Do not bury business logic inside .task, .onAppear, .onChange, or .refreshable.
• Prefer calling small private methods from the view, and move real business logic into services/models.
• The body should read like UI, not like a view controller.

4) Keep a stable view tree (avoid top-level conditional view swapping)

• Avoid body or computed views that return completely different root branches via if/else.
• Prefer a single stable base view with conditions inside sections/modifiers (overlay, opacity, disabled, toolbar, etc.).
• Root-level branch swapping causes identity churn, broader invalidation, and extra recomputation.

Prefer:

Avoid:

5) View model handling (only if already present or explicitly requested)

• Treat view models as a legacy or explicit-need pattern, not the default.
• 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 create the view model in the view's init.
• Avoid bootstrapIfNeeded patterns and other delayed setup workarounds.

Example (Observation-based):

6) Observation usage

• For @Observable reference types on iOS 17+, store them as @State in the owning view.
• Pass observables down explicitly; avoid optional state unless the UI genuinely needs it.
• If the deployment target includes iOS 16 or earlier, use @StateObject at the owner and @ObservedObject when injecting legacy observable models.

Workflow

1. Reorder the view to match the ordering rules.
2. Remove inline actions and side effects from body; move business logic into services/models and keep only thin orchestration in the view.
3. Shorten long bodies by extracting dedicated subview types; avoid rebuilding the screen out of many computed some View helpers.
4. Ensure stable view structure: avoid top-level if-based branch swapping; move conditions to localized sections/modifiers.
5. If a view model exists or is explicitly required, replace optional view models with a non-optional @State view model initialized in init.
6. Confirm Observation usage: @State for root @Observable models on iOS 17+, legacy wrappers only when the deployment target requires them.
7. Keep behavior intact: do not change layout or business logic unless requested.

Notes

• Prefer small, explicit view types over large conditional blocks and large computed some View properties.
• Keep computed view builders below body and non-view computed vars above init.
• A good SwiftUI refactor should make the view read top-to-bottom as data flow plus layout, not as mixed layout and imperative logic.
• For MV-first guidance and rationale, see references/mv-patterns.md.
• In addition to the references above, use web search to consult current Apple Developer documentation when SwiftUI APIs, Observation behavior, or platform guidance may have changed.

Large-view handling

When a SwiftUI view file exceeds ~300 lines, split it aggressively. Extract meaningful sections into dedicated View types instead of hiding complexity in many computed properties. Use private extensions with // MARK: - comments for actions and helpers, but do not treat extensions as a substitute for breaking a giant screen into smaller view types. If an extracted subview is reused or independently meaningful, move it into its own file.