Flux is the application architecture from Facebook that complements React. It's not a framework or a library, but rather a solution to a common problem; how to build scalable client-side applications.

With the Flux architecture, we can rethink how data flows inside our application. Flux makes sure that all our data flows only in a single direction. This helps us reason about how our application works, regardless of how small or large it is. With Flux, we can add a new functionality without exploding our application's complexity.

You might have noticed that both React and Flux share the same core concept; one-way data flow. That's why they naturally work well together. We know how data flows inside a React component, but how does Flux implement the one-way data flow?

With Flux, we separate the concerns of our application into four logical entities:

Actions are objects that we create when our application's state changes. For example, when our application...