Apple Sample Code

Study how Apple sample projects apply design patterns, architecture, and platform best practices in real code. Each analysis explains how a project structures features, manages state, defines responsibilities, and connects Apple frameworks to app behavior.

Inside one sample analysis

Building a Custom Catalog and Matching Audio

This ShazamKit sample provides a compact preview of the ownership, state flow, framework boundary, naming, and access-control details available on its full analysis page.

Architecture and ownership

flowchart LR
    App["FoodMathApp"] -->|"renders"| View["ContentView"]
    App -->|"owns @StateObject<br/>and injects"| Matcher["Matcher"]
    View -->|"requests"| Provider["CatalogProvider"]
    Provider -->|"builds"| Catalog["SHCustomCatalog"]
    View -->|"passes catalog"| Matcher
    Matcher -->|"publishes result"| View

What the analysis surfaces

Ownership: FoodMathApp creates a private @StateObject and injects it into ContentView; this is a lifecycle and composition boundary.
State flow: ContentView receives Matcher through the SwiftUI environment, while Matcher publishes the match result.
Framework boundary: CatalogProvider constructs SHCustomCatalog; ContentView passes the catalog into Matcher.

Reference code

Shared Source/App/FoodMathApp.swift:10

@main
struct FoodMathApp: App {
    @StateObject private var matcher = Matcher()

    var body: some Scene {
        WindowGroup {
            ContentView()
                .environmentObject(matcher)
        }
    }
}

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Start with a developer question

Who owns and mutates state? Follow construction, storage, observation, delegation, and lifetime instead of relying on type names.
Where does work execute? Inspect actor isolation, main-actor handoffs, queues, tasks, run loops, synchronization, and cancellation from source.
What does Apple call each responsibility? Compare real uses of ViewModel, Controller, Manager, Store, Coordinator, and related suffixes.
How is the project divided? Review targets, packages, feature or role folders, protocols, imports, and framework adapters.

Explore more

Patterns across Apple sample code compares recurring design patterns and architecture choices.
Frameworks and categories organizes analyses by framework and topic.
Apple Sample Code MCP makes the reviewed corpus available in Codex and Claude.
About this study explains why this project exists.