Redux中间件和Redux可观察的史诗有什么区别？

Question

I would like to understand when it is appropriate to use a redux middleware over a redux-observable epic (and vice versa).

From the redux middleware documentation

It provides a third-party extension point between dispatching an action, and the moment it reaches the reducer. People use Redux middleware for logging, crash reporting, talking to an asynchronous API, routing, and more.

From the redux-observable documentation

While you'll most commonly produce actions out in response to some action you received in, that's not actually a requirement! Once you're inside your Epic, use any Observable patterns you desire as long as anything output from the final, returned stream, is an action.

My understanding is that an action in a redux middleware may or may not hit a reducer and if it does, it may or may not result in a change of state. In an epic you can produce a new action which may or may not hit a reducer or result in a change of state.

It looks like both can be used to enable side effects so the difference between the two is becoming a bit blurry to me.

Question: Is the FRP foundation the only thing that sets them apart or are there specific events in the lifecycle of an application that are better dealt with a classic middleware or an epic?

Answer 1

"Middleware" are a general type of thing that can be used to customize a Redux store. redux-observable is a specific Redux middleware, which lets you use RxJS logic to interact with dispatched actions.