Redux is an open-source JavaScript library for managing application state.

Redux solves this problem by managing application’s state with a single global object called Store

Fundamentals

 Action
Store:

        Dispatcher
     Reducer

Data Flow

Redux-saga

Redux-saga is a redux middleware library, that is designed to make handling side effects in your redux app nice and simple.

It achieves this by leveraging an ES6 feature called Generators, allowing us to write asynchronous code that looks synchronous, and is very easy to test.

Middleware provides a third-party extension point between dispatching an action, and the moment it reaches the reducer

Redux-Saga