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)

Using RxJS to manage user input

Now we must implement the observables to listen to user input; they are going to be used to send messages to the server.

Let's implement the events.js file inside the client folder.

The first thing to do is to use the RxJS module:

var Rx = require('rx'); 

We want to send the user messages every time the user hits the Send message button or when the user hits enter in the message box.

For this reason, we need two observables, the first to trigger when the user clicks on the Send message button:

var sendPressedObservable = Rx.Observable 

This observable is simple and just propagates the event whenever the user clicks on the button.

The second observable will propagate the event whenever the user hits the Enter key in the message box:

var enterPressedObservable = Rx.Observable 
        var ENTER_KEY_CODE=13...