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)

Chapter 9. Composition

In the last chapter, we reviewed some of the key concepts from functional reactive programming using RxJS, including:

  • Which events an observable propagates
  • What are observables?
  • Review of some important operators:
    • Differences between the map() and flatMap() operators
    • A challenge to emulate an operator from another
    • Filter data
    • Aggregate data
  • Tests for an RxJS program
  • Mitigating the problem of backpressure
  • Combining observables

Paying attention to this review is crucial to have a better and clearer understanding of functional reactive programming, and with this knowledge we are more prepared for more advanced topics, such as some operators from the last chapter:

  • flatMapLatest()
  • flatMapFirst()
  • finally()
  • groupBy()
  • do()

In this chapter, we will learn a final topic before we move on to our final project. Using all the knowledge from this book, we already learned how we can combine observables, and now we will learn how we can compose transformations independently using a new concept called...