Fix TS definitions test for new Dispatch typing

[pelotom]

No description provided.

[timdorr]

BTW, there is another PR (#2671, that I busted with next updates just now), that has a similar, but different set of fixes: b9278d1

Any thoughts on the comparison between the two?

[pelotom]

By and large it's equivalent, but these definitions aren't quite right:

// dispatch.ts
declare module "../../" {
  export interface Dispatch<D = Action> {
    <R>(asyncAction: (dispatch: Dispatch<D>, getState: () => D) => R): R;
    // ^ `getState()` should not return the action type `D`
  }
}

// middleware.ts
declare module "../../" {
    export interface Dispatch<D> {
        <R,S>(asyncAction: (dispatch: Dispatch<D>, getState: () => S) => R): R;
        // ^ `getState()` should not be parameterized by the state type `S`; the type
        // of the state is not determined by the caller
    }
}

[timdorr]

Thanks. I'm starting to get my bearings with TS stuff, but our typings are really dense and I need some hand-holding :)

I think this looks good. Since we're now passing, this should get my other PRs unblocked. Thank you!

[pelotom]

No problem, looking forward to seeing these typings on master!