Add section about integration "redux-thunk" with typescript

[piotrwitek]

I see people still have issues using redux-thunk with typescript especially because poorly typed bindActionCreators. It would be great to add a section with reference use-case example and common pitfalls explained better that what we have now.

Related issues:
reduxjs/redux-thunk#224
#6 (comment)

[piotrwitek]

Hey everyone, I know that many people was asking for this so here you go. First iteration of integration for redux-thunk with typescript, that works perfect with both regular and thunk actions mixed together:

import { action, ThunkActionType } from 'typesafe-actions';

export const increment = () => action('INCREMENT');
export const add = (amount: number) => action('ADD', amount);
export const thunkIncrement = () => (dispatch: Dispatch) =>
  dispatch(action('THUNK_INCREMENT'));
export const thunkAdd = (amount: number) => (dispatch: Dispatch) =>
  dispatch(action('THUNK_ADD', amount));

const thunkActions = { thunkIncrement, thunkAdd, increment, add };

type Action = ThunkActionType<typeof thunkActions>;
// type Action = EmptyAction<"THUNK_INCREMENT"> | PayloadAction<"THUNK_ADD", number> | EmptyAction<"counters/INCREMENT"> | PayloadAction<"counters/ADD", number>

EDIT:
After analyzing redux-thunk use-cases I came to conclusion that above experimental ThunkActionType isn't very useful in the real world. It can only infer returned action type and thunk actions can dispatch multiple arbitrary actions imperatively in the thunk body and there is no way to infer that.