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)

Implementing the server

To implement our server, we need to implement the three parts of our system described in the previous example. We will first create our data source, then our WebSocket server, and finally our services and their tests.


As we have no interest in keep the history of messages nor in implementing a login for our server (the users are going to just type a name and this name will be used), we can use a simple observable to implement our DataSource; this DataSource will contain only the messages sent from user to user and broadcast messages.

Our DataSource must have two methods: the first to push new messages, and the second to listen to incoming messages. We can use a RxJS Subject to implement this behavior as it lets us push data to our observable. We could also user an observable using the create() method to create it from an arbitrary source, but the code with a Subject will be a lot easier to read and to understand:

let Rx = require('rx'); 
let messagesSubject...