Swift Reference

Modern Swift, explained with code.

Copy-ready patterns for Swift 6, SwiftUI, concurrency, SwiftData, Apple Intelligence and StoreKit 2 — each with the pitfalls that trip developers (and AI assistants) up.

🔶 Swift LanguageBeginner

Optionals

Represent a value that may be missing, and unwrap it safely with if let, guard let and ??.

🔶 Swift LanguageBeginner

Structs vs Classes

Value types vs reference types — and why SwiftUI and Swift concurrency favor structs.

🔶 Swift LanguageBeginner

Enums with Associated Values

Model a fixed set of states — each carrying its own data — and handle them exhaustively with switch.

🔶 Swift LanguageIntermediate

Protocols & Protocol Extensions

Define capabilities as contracts, add default behavior with extensions, and use some/any correctly.

🔶 Swift LanguageIntermediate

Closures & Capture Lists

Pass behavior as values, use trailing closure syntax, and avoid retain cycles with [weak self].

🔶 Swift LanguageIntermediate

Generics

Write reusable, type-safe code with generic functions, types and where constraints.

🔶 Swift LanguageBeginner

Error Handling (throws, do/catch, typed throws)

Throw and catch errors, convert with try? and use Swift 6 typed throws for precise error types.

Swift 2.0+ · typed throws Swift 6

📱 SwiftUIBeginner

@State & @Binding

Own simple view-local state with @State and share write access with child views through @Binding.

📱 SwiftUIIntermediate

@Observable (Observation framework)

The modern replacement for ObservableObject/@Published — fine-grained updates with less boilerplate.

📱 SwiftUIBeginner

NavigationStack & navigationDestination

Data-driven, type-safe navigation that supports deep links and programmatic push/pop.

📱 SwiftUIBeginner

List, ForEach & Identifiable

Render dynamic collections efficiently with stable identity, swipe actions and sections.

📱 SwiftUIIntermediate

.task & Loading Data

Start async work when a view appears — automatically cancelled when it disappears.

📱 SwiftUIIntermediate

Environment & Dependency Injection

Share models and system values down the view tree without passing them through every initializer.

iOS 17+ for @Observable in environment

📱 SwiftUIBeginner

Animations & Transitions

Animate state changes with withAnimation, springs, transitions and symbol effects.

iOS 13+ · phase/keyframe iOS 17+

⚡ ConcurrencyIntermediate

async / await

Write asynchronous code that reads top-to-bottom, with errors handled by normal try/catch.

Swift 5.5+ · iOS 13+

⚡ ConcurrencyAdvanced

Task, Cancellation & TaskGroup

Start concurrent work, cancel it cooperatively, and fan out a dynamic number of child tasks.

⚡ ConcurrencyAdvanced

Actors

Protect mutable state from data races — only one task touches an actor's state at a time.

⚡ ConcurrencyIntermediate

@MainActor & UI Updates

Guarantee UI code runs on the main thread — and understand Swift 6.2 default MainActor isolation.

Swift 5.5+ · default isolation option Swift 6.2

⚡ ConcurrencyAdvanced

Sendable & Swift 6 Data-Race Safety

Understand the Sendable checks behind most Swift 6 errors — and how to fix them properly.

Swift 5.5+ · enforced in Swift 6 language mode

🗄️ SwiftDataBeginner

@Model & ModelContainer

Turn a Swift class into a persistent model and wire the storage into your app with one modifier.

iOS 17+ · macOS 14+

🗄️ SwiftDataIntermediate

@Query, Sorting & #Predicate

Fetch models directly into a SwiftUI view — filtered, sorted and automatically kept up to date.

🧠 Apple IntelligenceIntermediate

Foundation Models Framework

Run Apple’s on-device language model from Swift — private, offline and free of API costs.

iOS 26+ · Apple Intelligence devices

🧠 Apple IntelligenceAdvanced

@Generable Guided Generation

Get typed Swift structs back from the model instead of parsing free-form text.

🧠 Apple IntelligenceIntermediate

App Intents for Siri & Shortcuts

Expose app actions to Siri, Spotlight, Shortcuts and Apple Intelligence with a small Swift type.

💳 StoreKit 2Intermediate

Products & Purchases

Load products, buy them and verify transactions with modern async StoreKit 2.

💳 StoreKit 2Advanced

Subscriptions & Entitlements

Show a native paywall and decide who has Pro access using current entitlements.

iOS 17+ (SubscriptionStoreView)

🛠️ Xcode & AI WorkflowBeginner

#Preview & Xcode Previews

Iterate on SwiftUI views instantly with multiple previews, sample data and traits.

🛠️ Xcode & AI WorkflowBeginner

AI-Assisted Swift Workflow

Use AI coding assistants to go faster without shipping code you do not understand.

Xcode 26 · any AI assistant

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