Functional Programming in Swift (iOS/macOS)

The book "Functional Programming in Swift" is a practical guide to applying the functional paradigm in iOS and macOS development. Unlike academic works, the author focuses on real-world tasks: data processing, state management, and writing testable and predictable code.

What the book is about:

• Fundamentals of the functional approach: pure functions, immutability, absence of side effects.
• Working with collections using map, filter, reduce, flatMap, compactMap.
• Function composition and currying for creating modular solutions.
• Functors, applicative functors, and monads (Optional, Result, Future/Promise).
• Managing asynchrony without callback hell using functional primitives.
• Integrating the functional style into an existing UIKit/SwiftUI project.
• Testing functional code: property-based testing, invariants.

Who this book is for:

• iOS/macOS developers who want to write safer and more concise code.
• Programmers transitioning from imperative languages (C++, Java, Python) to Swift.
• Developers familiar with Swift basics but wanting to master the functional paradigm.
• Anyone tired of mutable state and wanting to reduce the number of bugs.

What you will learn:

• How to replace loops and nested conditions with chains of transformations.
• How to design APIs using functional types (Result, Either, Writer).
• How to combine functions to build complex logic from simple building blocks.
• How to use functional approaches in SwiftUI for state management.
• How to write code that is easy to refactor and test.

The book contains over 50 code examples, analysis of common mistakes, and exercises for reinforcing the material. All examples are compatible with the latest versions of Swift and Xcode. Suitable for developers with at least 1 year of experience.

Dive into the world of functional programming in Swift and make your code clean, predictable, and elegant.