Redux - Alwynblake/seattle-javascript-401n12 GitHub Wiki

Redux is a predictable state container for JavaScript apps.
Instead of mutating the state directly, you specify the mutations you want to happen with plain objects called actions. Then you write a special function called a reducer to decide how every action transforms the entire application's state. In a typical Redux app, there is just a single store with a single root reducing function. As your app grows, you split the root reducer into smaller reducers independently operating on the different parts of the state tree. This is exactly like how there is just one root component in a React app, but it is composed out of many small components.
This architecture might seem like an overkill for a counter app, but the beauty of this pattern is how well it scales to large and complex apps. It also enables very powerful developer tools, because it is possible to trace every mutation to the action that caused it. You can record user sessions and reproduce them just by replaying every action.