Add extraThunkArgument to configureStore options

[jednano]

Related to #113, I would love the ability to provide an extra thunk argument via an extraThunkArgument option to configureStore.

const extraThunkArgument = { foo: 'bar' }
const store = configureStore<RootState, RootActions, typeof extraThunkArgument>({
  reducer: rootReducer,
  extraThunkArgument, 
})

The result of the thunk should be of the following type:

ThunkMiddleware<RootState, RootActions, typeof extraThunkArgument>

Basically, the types of configureStore should match pretty closely the types of Redux's StoreCreator. A fully typed example of a call to createStore would look like this:

const store = createStore<
	RootState,
	RootActions,
	{
		dispatch: ThunkDispatch<
			RootState,
			typeof extraThunkArgument,
			RootActions
		>
	},
	{}
>(rootReducer, app.loadState())

Furthermore, there should be a good strategy for mocking this store, perhaps with a similar approach to @jedmao/redux-mock-store?

export default configureMockStore<
  RootState,
  RootActions,
  ThunkDispatch<RootState, typeof extraThunkArgument, RootActions>
>(middlewares)

This, however, would be a separate dev dependency and perhaps a separate GitHub issue as well.

[markerikson]

Hey, thanks for filing this.

I'm a bit hesitant to explicitly add an option for this directly to configureStore itself, for a couple reasons:

• RSK aims to have the most common usages handled by default
• If you need to customize the default middleware, you can override the middleware argument and pass in your own list. That would include a customized thunk instance
• Conversely, it's also possible that people might have excluded the thunk middleware from the store setup, so that option might not apply.

Typings-wise, what happens if you do something like middleware: [thunk.withExtraArgument(someArg)] ? How does the resulting store type come out?

[markerikson]

Resolved by #192 .