In Chapter 6, Crafting Reusable Components, I introduced the container pattern for React components. The container component has state but it doesn't actually render any UI elements. Instead, it renders other React components and passes in its state as properties. Whenever the container state changes, the child components are re-rendered with new property values. This is unidirectional data flow.
Flux takes this idea and applies it to something called a store. A store is an abstract concept that holds application state. As far as I'm concerned, a React container is a perfectly valid Flux store. I'll have more to say about stores in a moment. First, I want you to understand why unidirectional data flows are advantageous.
There's a good chance that you've implemented a UI component that changes state, but you're not always sure how it happens. Was it the result of some event in another component? Was it a side-effect from some network call...
