Introducing RxSwift: Reactive Programming with Swift!

Chris Belanger

For the past six months, we’ve been working on a top-secret book project: RxSwift: Reactive Programming with Swift.

We revealed the book at our third annual tutorial conference, RWDevCon 2017, and the book is now available on the raywenderlich.com store!

To celebrate the book launch, we’ll release some free chapters on the site this week — and you can also grab a great discount on the book in our store.

Read on to see what the book is all about!

What is RxSwift?

Rx is one of the hottest topics in mobile app development. From international conferences to local meetups, it seems like everyone is talking about observables, side effects, and (gulp) schedulers.

And no wonder — Rx is a multi-platform standard, so whether it’s a web development conference, local Android meetup, or a Swift workshop, you might end up joining a multi-platform discussion on Rx.

The RxSwift library (part of the larger family of Rx ports across platforms and languages) lets you use your favorite Swift programming language in a completely new way. The somewhat difficult-to-handle asynchronous code in Swift becomes much easier and a lot saner to write with RxSwift.

What’s In the RxSwift Book?

In RxSwift: Reactive Programming with Swift, you’ll learn how RxSwift solves issues related to asynchronous programming. You’ll also master various reactive techniques, from observing simple data sequences, to combining and transforming asynchronous value streams, to designing the architecture and building production quality apps.

By the end of the book, you’ll have learned all about the ins and outs of RxSwift, you’ll have hands-on experience solving the challenges at the end of the chapters — and you’ll be well on your way to coming up with your own Rx patterns and solutions!

Here’s a detailed look at what’s inside the book:

Section I: Getting Started with RxSwift

The first section of the book covers RxSwift basics. Don’t skip this section, as you will be required to have a good understanding of how and why things work in the following sections.

  1. Hello RxSwift!: Learn about the reactive programming paradigm and what RxSwift can bring to your app.
  2. Observables: Now that you’re ready to use RxSwift and have learned some of the basic concepts, it’s time to play around with observables.
  3. Subjects:In this chapter, you’re going to learn about the different types of subjects in RxSwift, see how to work with each one and why you might choose one over another based on some common use cases.
  4. Observables and Subjects in Practice: In this chapter, you’ll use RxSwift and your new observable super-powers to create an app that lets users to create nice photo collages — the reactive way.

Learn the Zen of sequences in RxSwift!

Section II: Operators and Best Practices

In this section, once you’ve mastered the basics, you will move on to building more complex Rx code by using operators. Operators allow you to chain and compose little pieces of functionality to build up complex logic.

  1. Filtering Operators: This chapter will teach you about RxSwift’s filtering operators that you can use to apply conditional constraints to .next events, so that the subscriber only receives the elements it wants to deal with.
  2. Filtering Operators in Practice: In the previous chapter, you began your introduction to the functional aspect of RxSwift. In this chapter, you’re going to try using the filtering operators in a real-life app.
  3. Transforming Operators: In this chapter, you’re going to learn about one of the most important categories of operators in RxSwift: transforming operators.
  4. Transforming Operators in Practice: In this chapter, you’ll take an existing app and add RxSwift transforming operators as you learn more about map and flatMap, and in which situations you should use them in your code.
  5. Combining Operators: This chapter will show you several different ways to assemble sequences, and how to combine the data within each sequence.
  6. Combining Operators in Practice: You’ll get an opportunity to try some of the most powerful RxSwift operators. You’ll learn to solve problems similar to those you’ll face in your own applications.
  7. Time Based Operators: Managing the time dimension of your sequences is easy and straightforward. To learn about time-based operators, you’ll practice with an animated playground that visually demonstrates how data flows over time.

Leverage the power of operators in RxSwift!

Section III: iOS Apps with RxCocoa

Once you’ve mastered RxSwift’s basics and know how to use operators, you will move on to iOS specific APIs, which will allow you to use and integrate your RxSwift code with the existing iOS classes and UI controls.

  1. Beginning RxCocoa: In this chapter you’ll be introduced to another framework: RxCocoa. RxCocoa works on all platforms and targets the specific UI needs of iOS, watchOS, tvOS and macOS.
  2. Intermediate RxCocoa: Following on from Chapter 12, you’ll learn about some advanced RxCocoa integrations and how to create custom wrappers around existing UIKit components.

Learn how to create a reactive UI as you build a fully-featured app!

Section IV: Intermediate RxSwift/RxCocoa

In this section, you will look into more topics like building an error-handling strategy for your app, handling your networking needs the reactive way, writing Rx tests, and more.

  1. Error Handling in Practice: Even the best RxSwift developers can’t avoid encountering errors. You’ll learn how to deal with errors, how to manage error recovery through retries, or just surrender yourself to the universe and letting the errors go.
  2. Intro to Schedulers: This chapter will cover the beauty behind schedulers, where you’ll learn why the Rx abstraction is so powerful and why working with asynchronous programming is far less less painful than using locks or queues.
  3. Testing with RxTest: For all the reasons why you started reading this book and are excited to begin using RxSwift in your app projects, RxTest (and RxBlocking) may very soon have you excited to write tests against your RxSwift code, too.
  4. Creating Custom Reactive Extensions: In this chapter, you will create an extension to NSURLSession to manage the communication with an endpoint, as well as managing the cache and other things which are commonly part of a regular application.

There’s nothing mysterious about schedulers in RxSwift – they’re powerful and easy to use!

Section V: RxSwift Community Cookbook

Many of the available RxSwift-based libraries are created and maintained by the community – people just like you. In this section, we’ll look into a few of these projects and how you can use them in your own apps.

  1. Table and Collection Views: RxSwift not only comes with the tools to perfectly integrate observable sequences with tables and collections views, but also reduces the amount of boilerplate code by quite a lot.
  2. Action: Action exposes observables for errors, the current execution status, an observable of each work observable, guarantees that no new work starts when the previous has not completed, and generally is such a cool class that you don’t want to miss it!
  3. RxGesture: Gesture processing is a good candidate for reactive extensions. Gestures can be viewed as a stream of events, either discrete or continuous. Working with gestures normally involves using the target-action pattern, where you set some object as the gesture target and create a function to receive updates.
  4. RxRealm: A long time ago, in a parallel universe far away, developers who needed a database for their application had the choice between using the ubiquitous but tortuous Core Data, or creating custom wrappers for SQLite. Then Realm appeared, and using databases in applications became a breeze.
  5. RxAlamofire: One of the basic needs of modern mobile applications is the ability to query remote resources. RxAlamofire adds an idiomatic Rx layer to Alamofire, making it straightforward to integrate into your observable workflow.

Get a handle on some of the most popular RxSwift libraries, along with example code!

Section VI: Putting it All Together

This part of the book deals with app architecture and strategies for building production-quality, full-blown iOS applications. You will learn how to structure your project and explore a couple of different approaches to designing your data streams and the project navigation.

  1. MVVM with RxSwift: RxSwift is such a big topic that this book hasn’t covered application architecture in any detail yet. And this is mostly because RxSwift doesn’t enforce any particular architecture upon your app. However, since RxSwift and MVVM play very nicely together, this chapter is dedicated to the discussion of that specific architecture pattern.
  2. Building a Complete RxSwift App: To conclude the book, you’ll architect and code a small RxSwift application. The goal is not to use Rx “at all costs”, but rather to make design decisions that lead toa clean architecture with stable, predictable and modular behavior. The application is simple by design, to clearly present ideas you can use to architect your own applications.

Who Is this Book For?

This book is for iOS developers who already feel comfortable with iOS and Swift, and want to dive deep into development with RxSwift.

If you’re a complete beginner to iOS, we suggest you first read through the latest edition of the iOS Apprentice. That will give you a solid foundation of building iOS apps with Swift from the ground up but you might still need to learn more about intermediate level iOS development before you can work through all chapters in this book.

If you know the basics of iOS development but are new to Swift, we suggest you read through Swift Apprentice first, which goes through the features of Swift using playgrounds to teach the language.

You can find both of these books at our online store: store.raywenderlich.com.

Free RxSwift Chapters

To help celebrate the release of RxSwift: Reactive Programming with Swift, we are offering our readers a taste of what the book has in store.

We’ll be releasing two chapters from the book this week as tutorials on the site, complete with downloadable resources, that you can use to start your journey of learning RxSwift.

Introducing the RxSwift Book Authors

Check out the amazing team of authors behind this book:

Florent Pillet has been developing for mobile platforms since the last century and moved to iOS on day 1. He adopted reactive programming before Swift was announced and has been using RxSwift in production since 2015. A freelance developer, Florent also uses Rx on Android and likes working on tools for developers like the popular NSLogger when he’s not contracting for clients worldwide. Say hello to Florent on Twitter at @fpillet.

Junior Bontognali has been developing on iOS since the first iPhone and joined the RxSwift team in the early development stage. Based in Switzerland, when he’s not eating cheese or chocolate, he’s doing some cool stuff in the mobile space, without denying to work on other technologies. Other than that he organizes tech events, speaks and blogs. Say hello to Junior on Twitter at @bontoJR.

Marin Todorov is one of the founding members of the raywenderlich.com team and has worked on seven of the team’s books. Besides crafting code, Marin also enjoys blogging, teaching, and speaking at conferences. He happily open-sources code. You can find out more about Marin at www.underplot.com.

Scott Gardner has been developing iOS apps since 2010, Swift since the day it was announced, and RxSwift since before version 1. He’s authored several video courses, tutorials, and articles on iOS app development, presented at numerous conferences, meetups, and online events, and this is his second book. Say hello to Scott on Twitter at @scotteg.

Where to Go From Here?

There’s one final piece of good news.

You’ll receive an automatic $10 discount on the PDF version of the book when you buy it through our online store .

But this offer is only good for launch week, April 3-7, so grab it while you can! After that, the book goes back up to $54.99.

Check out the store page to take advantage of this offer: store.raywenderlich.com/products/rxswift.

The RxSwift book team and I hope you enjoy the book, and we can’t wait to hear about your RxSwift adventures!

Chris Belanger

Chris Belanger is the Book Team Lead and Lead Editor for raywenderlich.com. If there are words to wrangle or a paragraph to ponder, he‘s on the case.

In the programming world, Chris has over 20 years of experience with multiple database platforms, real-time industrial control systems, and enterprise healthcare information systems.

When he kicks back, you can usually find Chris with guitar in hand, looking for the nearest beach, or exploring the lakes and rivers in his part of the world in a canoe.

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