Functional Programming in Swift (iOS/macOS)

Modern iOS and macOS development requires not just knowledge of Swift syntax, but also the ability to write code that is easy to maintain, test, and extend. The book "Functional Programming in Swift" is a practical guide that will help you transition from an imperative style to a declarative one, using the power of the functional paradigm in the Apple ecosystem.

The author, Alexey Voronov, an experienced iOS developer with 10 years of experience, shows through real-world examples how to apply functional concepts to solve everyday tasks: from array processing to building complex asynchronous chains. You will learn how to make code more predictable, eliminate side effects, and reduce the number of bugs.

What you will learn from this book:

• Fundamentals of the functional approach: pure functions, data immutability, higher-order functions.
• Working with collections: map, filter, reduce, flatMap, compactMap — how and when to use them.
• Composition and currying: creating reusable functions from simple building blocks.
• Monads and functors: Optionals, Result, Future — working with optionality and errors without force unwrapping.
• Functional patterns: Reader, Writer, State — managing configuration and logs.
• Testing: writing tests for functional code, dependency injection through functions.
• Practical examples: working with Combine, SwiftUI, network requests, and Core Data in a functional style.

Who this book is for:

• iOS developers who want to improve code quality.
• Programmers familiar with the basics of Swift but looking to master functional approaches.
• Team leads and architects seeking ways to make the codebase more resilient to change.

The book contains over 50 practical examples, ready to use in Xcode. All examples are accompanied by step-by-step comments and explanations. You will learn to think in terms of functions rather than classes, and see how functional code becomes more concise and safer.

Whether you are creating a simple notes app or a complex financial service, the principles described in this book will help you write code that will delight you and your team for years to come.