Add Dispatch overload to Redux module.

[threehams]

Similarly to the bindActionCreators overload, this extends Redux to dispatch thunks and provide the correct return values. This prevents us from needing to build thunk support into react-redux.

I could use some advice on testing this one. The following is an error, as it appears that this Dispatch import receives the interface before the redux-thunk declarations are merged:

import { Dispatch } from "redux";
type ExtendedDispatch = Dispatch<ThunkResult<boolean>>;

Understanding what's happening here might help me remove inlined thunk logic from connect() typings in react-redux.

I've tested this in a real-world application with react-redux hooks typings (https://github.com/MrWolfZ/DefinitelyTyped/pull/3) in two forms:

const thunkAction = () => {
  return (dispatch: Dispatch, getState: () => State) => {
    return dispatch({ type: "SET_STATE" });
  };
};
const dispatch = useDispatch();
// typeof result === { type: "SET_STATE" }
const result = dispatch(thunkAction()) 

// typeof result === { type: "SET_STATE" }
const result = dispatch((thunkDispatch, getState) => { // correctly infers dispatch + getState
  return thunkDispatch();
});

[demian85]

What is the status of this?

[threehams]

The status is that it doesn't work, I don't know why it doesn't work, and I'm trying to set up a minimal repo to make it easier to understand the interaction between redux + libraries that extend redux.

[ValeryVS]

@threehams
I think, I solved this

declare module "redux" {
  import {ThunkAction} from "redux-thunk";

  /*
   * Overload to add thunk support to Redux's dispatch() function.
   * Useful for react-redux or any other library which could use this type.
   */
  export interface Dispatch<
    TBasicAction extends Action,
  > {
    <TReturnType, TState, TExtraThunkArg>(
      thunkAction: ThunkAction<TReturnType, TState, TExtraThunkArg, TBasicAction>
    ): TReturnType;
  }

 /// override bindActionCreators
}

[threehams]

Thanks, I was going to ask if you could open this in a separate PR. I'm not using redux / redux-thunk` much at the moment.