Bringing robust navigation structure to your SwiftUI app

At a glance

Project structure

Source bundle/
└── NavigationCookbook/
    ├── NavigationCookbookApp.swift
    ├── Models/
    │   ├── NavigationModel.swift
    │   ├── DataModel.swift
    │   ├── Recipe.swift
    │   ├── Category.swift
    │   ├── Experience.swift
    │   └── Ingredient.swift
    └── Views/
        ├── ContentView.swift
        ├── StackContentView.swift
        ├── ThreeColumnContentView.swift
        ├── TwoColumnContentView.swift
        └── ContinueButton.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 4 project/configuration file(s) and 24 source declaration(s).

Overall architecture

flowchart LR
    N1["NavigationCookbookApp"]
    N2["ContentView"]
    N3["DataModel"]
    N4["SwiftUI APIs"]
    N1 --> N2
    N2 --> N3
    N3 --> N4

Reference code

NavigationCookbook/NavigationCookbookApp.swift:11 — architecture anchor

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

Interpretation

The arrows summarize the source-visible entry, role-named types or folders, and framework direction; when nodes come from structural folders, the sequence is a high-level interpretation rather than proof that every adjacent node calls the next. Ownership is claimed only where the next section cites a stored property or assignment. The diagram is intentionally limited to the dominant path into SwiftUI.

Ownership and state

classDiagram
    NavigationModel o-- Category : selectedCategory
    NavigationModel *-- Array : recipePath
    NavigationModel o-- NavigationSplitViewVisibility : columnVisibility
    NavigationModel *-- JSONDecoder : decoder

Ownership evidence

NavigationCookbook/Models/NavigationModel.swift:16 — stored dependency or nearest verified ownership anchor

    var selectedCategory: Category?
    
    /// The homogenous navigation state used by the app's navigation stacks.
    var recipePath: [Recipe]
    
    /// The leading columns' visibility state used by the app's navigation split views.
    var columnVisibility: NavigationSplitViewVisibility

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

NavigationCookbook/NavigationCookbookApp.swift:12 — representative type boundary

struct NavigationCookbookApp: App {
    // ...
}

No local protocol conformance is claimed as protocol-oriented design; external framework conformances are listed only as dependencies.

Access control

Reference code

NavigationCookbook/Models/DataModel.swift:14 — representative boundary

    private(set) var recipes: [Recipe]

    /// A dictionary of recipes, each grouped by its associated unique identifier.
    private var recipesById: [Recipe.ID: Recipe] = [:]

    /// The shared singleton data model object.
    static let shared: DataModel = {
        // ...
    }()

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: NavigationCookbookApp; Model: DataModel, NavigationModel; View: ContentView, StackContentView, ThreeColumnContentView, TwoColumnContentView.
• Protocols: no local protocol declaration in the scanned source.
• Methods: load, save, encode, recipes.
• Files: NavigationCookbook/NavigationCookbookApp.swift, NavigationCookbook/Models/NavigationModel.swift, NavigationCookbook/Models/DataModel.swift, NavigationCookbook/Views/ContentView.swift, NavigationCookbook/Views/StackContentView.swift, NavigationCookbook/Views/ThreeColumnContentView.swift.

Architecture takeaways

• NavigationCookbookApp is the main source-visible entry or composition anchor for this sample.
• Framework work reaches SwiftUI 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.
• The source does not justify labeling the design protocol-oriented.

Source map

• Official Apple documentation