Flux is not a library, or a framework. It is an architecture that Facebook uses internally while working with React, which follows the concept of unidirectional data flow.
The core idea of the flux architecture is the unidirectional flow of data in the application.
Flex consists of four major parts: Dispatcher, Stores, Views and Actions.
Actions: Actions are nothing but events that are fired from the views (or from other places as well) to the store. These actions flow via the dispatcher (we will cover dispatcher soon). Dispatcher exposes a way that allows us to fire an action to the store along with the data and type.
... read the whole story at medium.com.