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 8. More about Operators

In the last chapter, we learned how to handle errors in our reactive applications; we saw that, if we do nothing to handle errors on our observables, that they will be propagated, notifying all the observers of that observable and stopping the observable without ever calling the onCompleted() method of the observers. Besides that we learned a set of operators to change this behavior and have more control over errors, as follows:

  • catch()
  • onErrorResumeNext()
  • retry()
  • mergeDelayError()

These operators give us more control over when to propagate the error and what to do in the event of an error.

Another really important lesson from the last chapter was the implementation of tests for programs using functional reactive programming, as on this paradigm we are always using asynchronous computation and our test needs to be ready to support this behavior.

The nature of functional reactive programming lets us decouple the source of our data from the effects of the occurrence...