Book Image

Mastering Reactive JavaScript

By : Erich de Souza Oliveira
Book Image

Mastering Reactive JavaScript

By: Erich de Souza Oliveira

Overview of this book

If you’re struggling to handle a large amount of data and don’t know how to improve your code readability, then reactive programming is the right solution for you. It lets you describe how your code behaves when changes happen and makes it easier to deal with real-time data. This book will teach you what reactive programming is, and how you can use it to write better applications. The book starts with the basics of reactive programming, what Reactive Extensions is, and how can you use it in JavaScript along with some reactive code using Bacon. Next, you’ll discover what an Observable and an Observer are and when to use them.You'll also find out how you can query data through operators, and how to use schedulers to react to changes. Moving on, you’ll explore the RxJs API, be introduced to the problem of data traffic (backpressure), and see how you can mitigate it. You’ll also learn about other important operators that can help improve your code readability, and you’ll see how to use transducers to compose operators. At the end of the book, you’ll get hands-on experience of using RxJs, and will create a real-time web chat using RxJs on the client and server, providing you with the complete package to master RxJs.
Table of Contents (11 chapters)

Chapter 7. Something is Wrong - Testing and Dealing with Errors

In the last chapter we learned about a powerful tool to increase the reuse and readability of our code. This tool is a combination of observables to create new sources of data. We also learned how we can run multiple asynchronous observables in parallel.

The most important operators we learned in the previous chapter are:

  • concat()
  • merge()
  • forkJoin()
  • zip()

The use of this operators can help us to avoid code repetition, giving us one very important mantra for readable code: Don't Repeat Yourself (DRY).

In this chapter, we will focus on two very important issues, not only for programs implemented using functional reactive programming, but for all programs:

  • We will see what happens to an observable when an error occurs and what we can do to treat this error and ensure our code keeps running as expected.
  • On the other hand, one of the coolest things about functional reactive programming is the ability to decouple the source of your data from...