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 transducers with RxJS

In the last section, we learned how we can apply a transducer to the most simple iterable object in JavaScript, an array. But we are more interested in how we can use this tool in functional reactive programming using RxJS.

Using transducers with RxJS we can see performance improvements, as we will avoid the creation of intermediate observable sequences and can improve the overall quality of our code with the composition of transformations.

To use a transducer in RxJS we need to use the transduce operator of the RxJS library; this operator has the following signature:


It receives only one mandatory argument:

  • transducer: It is the transducer transformation to be applied on the observable sequence

The transduce operator, like any other observable operator, returns a new operator, but as we can compose several transformations inside a single transducer we will create only one new observable.


Imagine an observable where we apply two...