Update applyMiddleware enhancer to use new createStore signature

[acdlite]

3.1 changed the signature of createStore(). This isn't considered a breaking change because existing enhancers will continue to work; however, going forward, it should be expected that a store enhancer returns a createStore function with the same signature as its input.

See https://twitter.com/acdlite/status/692772885186764802 for context

Still needs tests :)

[gaearon]

Maybe just ...rest? Not that enhancers ever have to deal with other enhancers.

[acdlite]

Yeah true. Although let's ask the question: should the enhancer passed to createStore be applied before or after the enhancer in question (applyMiddleware in this case)?

I think this is right (before) but... hmm.

[gaearon]

We don't ever want to encourage mixing both patterns. We'll transition docs to only use the new pattern, and the fact that the old one works will become an implementation detail.

[acdlite]

Even if we don't encourage it, I still think it's important as an implementation detail. At the least, it will be important for enhancer authors.

Problem in a nutshell:

const finalCreateStore = DevTools.instrument()(createStore)
const store = finalCreateStore(
  reducer,
  initialState,
  applyMiddleware(thunk, logger)
)

Which gets executed first: the DevTools, or the middleware?

[gaearon]

In this case, middleware will wrap the previously wrapped-with-DevTools function.
Specifying enhancer means specifying "the last wrapper".
Seems right to me.

(But really, nobody should do it)

[gaearon]

I trust that this works but please feel free to add tests. I'll release it as a patch bump now.

[gaearon]

Out in 3.1.1.

[acdlite]

In this case, middleware will wrap the previously wrapped-with-DevTools function.

@gaearon I don't think that's right. applyMiddleware() gets applied first because it's passed all the way through to the base createStore().

[gaearon]

Oh, right. Lol this is counter-intuitive. But then again, it's not a breaking change since it's a new way of doing things. I don't think people will mess this up in their apps but we'll see. Even if they do mess up, we'll just offer to use the new way.

[acdlite]

Alright as long as we're aware of it :)