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)

The bacon.js observables

In functional reactive programming, an observable is an object where you can listen for events. This way, you can, for instance, create an observable for a button and then listen and act when a click happens.

The bacon.js gives you two flavors of an observable: the first one is EventStream and the other is Property. We will see the difference between the two objects later. To listen to events in an observable (or subscribe to an observable), you can use the onValue()method with a callback. So if you want to log every event in an EventStream, you can use the following code:



We will see how to create an EventStream in more detail later.

As we saw in the example in the last chapter, we can transform our observable using bacon.js operators. These operators let us filter, combine, map, buffer, and do a lot of other interesting things with our EventStream.

An observable can either finish or stay open...