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)

Other important operators


Some important operators from RxJS don't have a perfect match with the groups of operators we learned so far, but they can easily solve some complex and specific problems with a few lines of code, making you feel like a magician when using them. Now we are going to learn them.

The flatMapLatest() operator

This operator is similar to the flatMap() operator, but it only propagates items from the most recently transformed observable.

Imagine a search as you type feature. In this feature, for every key stroke you will do a search and present the current result in the screen; if you are accessing external resources such as a database or an API, some searches can take more time than others, and the naive implementation of this search (using flatMap() for instance) might show wrong results. Look at this example:

  1. A search box to search names in a database.
  2. The user types the letter J and starts a search for all available names starting with the letter J.
  3. The user types the letter...