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

As we discussed in previous sections, transducers are a way to compose algorithmic transformations over iterable objects; to see this in action, let's first use a transducer in the most simple iterable object, an array.

To run a transducer over an array we first need a method to run a given transformation in a given iterable object.

For this we use the into() method, which has the following signature:


It receives three parameters and they are all mandatory:

  • emptyIterable: It is an empty iterable used to store the result of the application of the transformation over the iterable object
  • transformation: It is the function or transducers to be applied over the iterable object
  • iterable: It is the iterable object to be transformed

With the usage of this function we can implement transformations over an array, let's see how we can implement a simple map with it:

var t = require('transducers-js'); 

var iterableObject = [1,2,3,4]...