Why Redux?

To get started with this book, it's interesting to know what Redux does and what problem it's designed to solve.

In 2015, Redux was created by Dan Abramov, who began writing the first Redux implementation while preparing for a conference talk at React Europe, and Andrew Clark. Redux is a predictable state container for JavaScript applications; in other words, it is a utility tool to manage global states, which means data that is reachable across many parts of your application.

Where I used to work, we always asked the same question before starting a project: do we really need Redux? The problem we found is that when your application gets more complex, with more components that need to pass props down from a parent component to child components, the more complex the project becomes to read and improve. In short, it becomes unmaintainable.

This is an example of a common architecture of a basic application that passes down props from a parent component to child components:

Figure 1.1 – React architecture without Redux

That's where Redux joins the game. Redux eases these complexities, providing patterns and tools that make it easier to understand when, where, why, and how the state will be updated, and how your application logic will behave when those changes occur.

Redux will help when we need to do the following tasks:

• Manage large amounts of application state that are needed in many places.
• Manage business logic that is complex to update.
• Create an app that will be maintained by many people.

A year after releasing React, Facebook published the Flux architecture on social media. Flux is more of a pattern than a framework; it eschews Model-View-Controller (MVC) in favor of a unidirectional data flow. When a user interacts with the user interface, the user interface propagates an action through a singleton dispatcher to many stores that hold the application's data, which updates all of the user interfaces that are affected. Flux architecture became really popular, and so many implementations appeared, too, but the most popular was Redux; the adoption of Redux was quickly adopted by the React community, and it soon became common to teach the use of React and Redux together.

Now that we know why Redux is interesting for our projects and why it was created, we should look at what frontend technologies for state management existed before Redux entered the game.