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)

When do I need to combine observables?


One of the main advantages of functional reactive programming is how easy it makes reusing code, as we detach the source of data (observable) to the transformations we do on this data (operators) to the effect it causes when it happens (action taken by an observer), we can easily reuse each part of our code.

In the previous chapters, we saw how we can reuse an observable adding multiple observers to it. Now we can go one step further and combine these observables to create a new source of data; this will give us even more power.

When we combine (specifically when we concatenate) observables we can also avoid repeating code that is aligned with one of the main concepts of good code, which is Don't Repeat Yourself (DRY).

One simple and easy to understand example of combining observables to avoid subscribing to two observables can happen in a common task. Imagine that we want to implement a search tool in a website. On our search tool we want to do the search...