Food Truck: Building a SwiftUI multiplatform app

At a glance

Project structure

Source bundle/
├── App/
│   ├── App.swift
│   ├── Store/
│   │   ├── SubscriptionStoreView.swift
│   │   └── UnlockFeatureView.swift
│   ├── Account/
│   │   └── SignUpView.swift
│   └── Truck/
│       └── TruckView.swift
├── Widgets/
│   └── Widgets.swift
└── FoodTruckKit/
    └── Sources/
        ├── Donut/
        │   ├── DonutBoxView.swift
        │   └── DonutView.swift
        ├── Model/
        │   └── FoodTruckModel.swift
        ├── Order/
        │   └── OrderGenerator.swift
        ├── Store/
        │   └── StoreMessagesManager.swift
        └── Account/
            └── AccountStore.swift

Structure observations

• Architecturally prominent files are ranked from entry points and role-named declarations; resource-only paths are omitted.
• Primary languages: Swift.
• The verified tree contains 11 project/configuration file(s) and 160 source declaration(s).

Overall architecture

flowchart LR
    Bundle["Sample bundle"]
    V1["App"]
    V2["Widgets"]
    Boundary["SwiftUI APIs"]
    Bundle --> V1
    V1 --> Boundary
    Bundle --> V2
    V2 --> Boundary

Reference code

App/App.swift:15 — architecture anchor

@main
struct FoodTruckApp: App {
    // ...
}

Interpretation

The branches represent separate entry-bearing project variants in the downloaded bundle, not runtime calls between those variants. Each branch is intentionally collapsed at the documented framework boundary; the detailed target-local flow remains in the cited files. Ownership is claimed only where the next section cites a stored property or assignment.

Ownership and state

classDiagram
    FoodTruckApp *-- FoodTruckModel : model
    FoodTruckApp *-- AccountStore : accountStore
    SignUpView o-- FoodTruckModel : model
    SignUpView o-- AccountStore : accountStore

Ownership evidence

App/App.swift:18 — stored dependency or nearest verified ownership anchor

@main
struct FoodTruckApp: App {
    // ...
    @StateObject private var model = FoodTruckModel()
    // ...
}

Composition arrows indicate a source-visible construction expression or locally owned value state; aggregation means the owner stores or receives a dependency without proving exclusive lifetime ownership.

Class and protocol design

FoodTruckKit/Sources/Donut/Ingredients/Ingredient.swift:10 — representative type boundary

public protocol Ingredient: Identifiable, Hashable {
    var id: String { get }
    var name: String { get }
    var flavors: FlavorProfile { get }
    var imageAssetName: String { get }
    static var imageAssetPrefix: String { get }
}

The source explicitly defines local protocol relationships: Dough → Ingredient, Glaze → Ingredient, Topping → Ingredient.

Access control

Reference code

App/Account/AccountView.swift:16 — representative boundary

    @EnvironmentObject private var accountStore: AccountStore
    @Environment(\.authorizationController) private var authorizationController
    
    @State private var isSignUpSheetPresented = false
    @State private var isSignOutAlertPresented = false

Swift declarations without a modifier are internal; explicit private, fileprivate, private(set), public, or open entries above are interpreted by language semantics. Objective-C/C samples instead rely on header and implementation boundaries, which are not equivalent to Swift lexical privacy.

Logic ownership and placement

Design patterns

Naming conventions

• Types: App: FoodTruckApp; Controller: Controller, StoreProductController, StoreSubscriptionController; Generator: OrderGenerator, SeededRandomGenerator; Manager: StoreMessagesManager; Model: FoodTruckModel; Provider: Provider, TruckActivityPreviewProvider; Renderer: DonutRenderer; Store: AccountStore.
• Protocols: Ingredient.
• Methods: binding, subscriptionOptionCell, savings, applyKerning, signUp, dailyOrderSummaries, monthlyOrderSummaries, donuts.
• Files: App/Store/SubscriptionStoreView.swift, Widgets/Widgets.swift, App/Account/SignUpView.swift, FoodTruckKit/Sources/Donut/DonutBoxView.swift, FoodTruckKit/Sources/Donut/DonutView.swift, FoodTruckKit/Sources/Model/FoodTruckModel.swift.

Architecture takeaways

• App is the main source-visible entry or composition anchor for this sample.
• Framework work reaches SwiftUI, FoodTruckKit, StoreKit, WidgetKit through a deliberately small high-level chain; the detailed API graph remains inside the cited implementation files.
• Stored-property evidence identifies lifecycle collaboration; it does not by itself prove exclusive object ownership.
• Access-control conclusions separate verified language visibility from the likely design rationale.
• Local protocol relationships provide an explicit substitution boundary.

Source map

• Official Apple documentation