Combine: Asynchronous Programming With Swift

Learn all about declarative asynchronous programming with Swift using the Combine framework!

Writing asynchronous code can be challenging, with a variety of possible interfaces to represent, perform, and consume asynchronous work — delegates, notification center, KVO, closures, etc. Juggling all of these different mechanisms can be somewhat overwhelming. Does it really have to be this hard? Not anymore!

With Apple’s introduction of the Combine framework in WWDC 2019, declarative and reactive programming in Swift have become a meaningful aspect of the language and a game-changer in how developers perform and compose pieces of asynchronous work, making it a must-have tool at your disposal.

The introduction of Combine as a built-in framework in Apple’s ecosystem is promising news to developers who were interested in frameworks such as RxSwift or ReactiveSwift, but didn’t want the overhead of a third-party dependency. And while experience with either of the above is useful, it’s not a prerequisite for this book. You’ll learn everything from the ground up to become a true Combine master.

Combine is Apple’s framework to work with asynchronous events in a unified and reactive way that ensures your app is always up to date based on the latest state of its data.

What are these asynchronous events, you might ask? Anything that happens over time in your application can be represented by what is known as a Combine Publisher — network requests, user input, notifications, KVO, and much more. And since Combine unifies all of these different mechanisms under a single interface, this opens the door to interesting and powerful ways of composing logic and work in a declarative and universal way.

Swift Apprentice: Beyond the Basics

Swift Apprentice: Beyond the Basics is the sequel to Swift Apprentice: Fundamentals and explores additional Swift programming concepts. These topics include such things as access control, code organization, testing, property wrappers, result builders, concurrency, value semantics, and memory management, presenting them using interactive playgrounds that the reader can follow along with.

SwiftUI Apprentice

SwiftUI Apprentice is a series of epic-length tutorials where you’ll learn to build three complete apps from scratch, using Apple’s new user interface technology: SwiftUI! Each app is more advanced than the one before, and together, they cover everything to make your own apps using SwiftUI. By the end of the book, you’ll be experienced enough to turn your ideas into real apps you can sell on the App Store. These tutorials have easy to follow step-by-step instructions and consist of more than pages and illustrations! You also get full source code, image files, and other resources you can re-use for your own projects.

If you’re new to iOS and Swift, or to programming in general, learning how to write an app can seem incredibly overwhelming. That’s why you need a guide that:

You’ll start at the very beginning. The first section assumes you have little to no knowledge of programming in Swift for iOS but still shows you how to build an entire fitness app from scratch using SwiftUI. SwiftUI Apprentice doesn’t cover every single feature of iOS; it focuses on the absolutely essential ones. Instead of just covering a list of features, SwiftUI Apprentice does something much more important: It explains how all the building blocks fit together and what is involved in building real apps. You’re not going to create quick example programs that demonstrate how to accomplish a single feature. Instead, you’ll develop complete, fully-formed apps, with beautiful, professionally-designed user interfaces, that are good enough to submit to the App Store!

Our other book on building apps with SwiftUI, SwiftUI by Tutorials, is designed for developers who have a solid background in iOS development and are looking to make the leap from building apps with UIKit, to building apps with SwiftUI.

This book, SwiftUI Apprentice, is designed to teach new developers how to build iOS apps, using a SwiftUI-first approach. Its goal is to teach you fundamental development practices as you build out some fully-functional and great-looking apps!