Functional Programming in Swift for iOS and macOS

This book is a practical guide to functional programming in Swift for iOS and macOS development. Unlike classic textbooks, the focus is not on theory but on real-world tasks that every programmer faces: data processing, state management, working with asynchrony, and building reliable architectures.

Who this book is for:

• iOS/macOS developers who want to write cleaner and more predictable code;
• programmers familiar with OOP in Swift but wanting to master the functional style;
• students and junior developers who want to deepen their understanding of programming paradigms;
• anyone tired of side effects and mutable state in their projects.

What you will learn:

• Basic principles: immutability, pure functions, higher-order functions;
• Working with closures and their effective use in SwiftUI and UIKit;
• Function composition and building data processing pipelines;
• Monads and functors in practice: Optional, Result, Array as examples;
• Functional collection processing: map, filter, reduce, flatMap, compactMap;
• Managing side effects with the IO monad and Effect;
• Combining the functional approach with OOP and protocol-oriented programming;
• Practical examples for iOS: functional form validation, mutation-free networking, reactive chains.

Why you should read it: Functional programming helps avoid many runtime errors, simplifies testing, and makes code more readable. The book contains no dry academic theory — each principle is explained with examples from real iOS and macOS development. You will learn to write declarative code that is easy to maintain and extend.

The book is suitable for both beginners and experienced developers — the material is structured from simple to complex, with clear examples and explanations. After reading, you will be able to apply functional techniques in your Swift projects, improving code quality and reliability.