Design Patterns in Swift (iOS/macOS)

The book "Design Patterns in Swift (iOS/macOS)" is a practical guide for developers aiming to build scalable, maintainable, and testable applications for the Apple ecosystem. The author, an experienced iOS engineer, systematically breaks down classic design patterns (GoF) in the context of modern Swift, SwiftUI, and UIKit.

What is this book about?

The book covers three main groups of patterns:

• Creational Patterns: Singleton, Factory Method, Abstract Factory, Builder, Prototype — managing object creation without binding to specific classes.
• Structural Patterns: Adapter, Bridge, Composite, Decorator, Facade, Flyweight, Proxy — organizing efficient and flexible connections between components.
• Behavioral Patterns: Chain of Responsibility, Command, Interpreter, Iterator, Mediator, Memento, Observer, State, Strategy, Template Method, Visitor — distributing responsibilities and algorithms between objects.

Each pattern is examined through the lens of real-world iOS/macOS development tasks: working with Core Data, URLSession, SwiftUI Data Flow, multithreading with GCD/OperationQueue, animations, and UI components.

Who is this book for?

• Junior and Middle iOS/macOS developers who want to move from "just working code" to architecturally sound solutions.
• Developers transitioning from other languages (Java, C#, Python) to Swift — patterns are universal, but their implementation in Swift has its own nuances.
• Tech leads and architects looking to systematize knowledge and implement best practices within their team.

What will you learn?

• How to avoid anti-patterns (Massive View Controller, God Object, Spaghetti Code).
• How to combine multiple patterns to build a clean architecture (MVVM + Coordinator + Factory).
• How to adapt classic patterns for SwiftUI (ObservableObject, @State, @Binding, Environment).
• How to test code built on patterns using XCTest and mocks.
• How to refactor legacy projects by introducing patterns incrementally.

All code examples are available in the repository and are written in current versions of Swift 5.9+ and Xcode 15+. The book is suitable both for self-study and for use as a reference in daily work.

Make your code more predictable, flexible, and professional with design patterns in Swift!