Book Image

Architecting Angular Applications with Redux, RxJS, and NgRx

By : Christoffer Noring
Book Image

Architecting Angular Applications with Redux, RxJS, and NgRx

By: Christoffer Noring

Overview of this book

Managing the state of large-scale web applications is a highly challenging task with the need to align different components, backends, and web workers harmoniously. When it comes to Angular, you can use NgRx, which combines the simplicity of Redux with the reactive programming power of RxJS to build your application architecture, making your code elegant and easy to reason about, debug, and test. In this book, we start by looking at the different ways of architecting Angular applications and some of the patterns that are involved in it. This will be followed by a discussion on one-way data flow, the Flux pattern, and the origin of Redux. The book introduces you to declarative programming or, more precisely, functional programming and talks about its advantages. We then move on to the reactive programming paradigm. Reactive programming is a concept heavily used in Angular and is at the core of NgRx. Later, we look at RxJS, as a library and master it. We thoroughly describe how Redux works and how to implement it from scratch. The two last chapters of the book cover everything NgRx has to offer in terms of core functionality and supporting libraries, including how to build a micro implementation of NgRx. This book will empower you to not only use Redux and NgRx to the fullest, but also feel confident in building your own version, should you need it.
Table of Contents (12 chapters)

Problems with structuring async code – callback hell

In the previous section, we introduced the callback pattern as a way to deal with asynchronous calls. The pattern offers a structured way of dealing with such calls, in that we can always know what to expect in its method signature; the error is the first parameter, the second parameter is the response, and so on. But the pattern does have its shortcomings. The shortcomings might not be obvious at first, because you might only call the code like this:

openFile('filename', (err, content) => {
console.log( content );


What we see here is how we invoke the method openFile(). Once that runs to completion, the callback is called and, inside of the callback, we continue invoking statement4 and statement5.

This looks okay in the sense that it is still readable. The...