/swiftui-view-refactor

name: swiftui-view-refactor
description: Refactor and review SwiftUI view files with strong defaults for small dedicated subviews, MV-over-MVVM data flow, stable view trees, explicit dependency injection, and correct Observation usage. Use when cleaning up a SwiftUI view, splitting long bodies, removing inline actions or side effects, reducing computed `some View` helpers, or standardizing `@Observable` and view model initialization patterns.

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(title: title, subtitle: subtitle)
        FilterSection(
            filterOptions: filterOptions,
            selectedFilter: $selectedFilter
        )
        ResultsSection(items: filteredItems)
        FooterSection()
    }
}

private struct HeaderSection: View {
    let title: String
    let subtitle: String

    var body: some View {
        VStack(alignment: .leading, spacing: 6) {
            Text(title).font(.title2)
            Text(subtitle).font(.subheadline)
        }
    }
}

private struct FilterSection: View {
    let filterOptions: [FilterOption]
    @Binding var selectedFilter: FilterOption

    var body: some View {
        ScrollView(.horizontal, showsIndicators: false) {
            HStack {
                ForEach(filterOptions, id: \.self) { option in
                    FilterChip(option: option, isSelected: option == selectedFilter)
                        .onTapGesture { selectedFilter = option }
                }
            }
        }
    }
}

Avoid:

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)
    }
}

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.

Button("Save", action: save)
    .disabled(isSaving)

.task(id: searchText) {
    await reload(for: searchText)
}

private func save() {
    Task { await saveAsync() }
}

private func reload(for searchText: String) async {
    guard !searchText.isEmpty else {
        results = []
        return
    }
    await searchService.search(searchText)
}

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:

var body: some View {
    List {
        documentsListContent
    }
    .toolbar {
        if canEdit {
            editToolbar
        }
    }
}

Avoid:

var documentsListView: some View {
    if canEdit {
        editableDocumentsList
    } else {
        readOnlyDocumentsList
    }
}

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):

@State private var viewModel: SomeViewModel

init(dependency: Dependency) {
    _viewModel = State(initialValue: SomeViewModel(dependency: dependency))
}

6) Observation usage

• For `@Observable` reference types on iOS 17+, store them as `@State` in the owning view.
• P