Saga vs Thunk - jellyfish-tom/TIL GitHub Wiki
Redux-Saga and Thunk are middleware libraries that allow the redux store to interact with REST APIs asynchronously. The process of making API calls and interactions with external resources is called side effects. So in principle, saga and thunk middlewares help manage these side effects.
The benefit of Redux Saga compared to Redux Thunk is that you can more easily test your asynchronous data flow inside an application.