index.ts

import { combineReducers } from '@reduxjs/toolkit'

import clicksReducer from './counter'

const clicks = { count: clicksReducer }

export let rootReducer = combineReducers({
  ...clicks
})

export default function createReducer(injectedReducers = {}) {
  rootReducer = combineReducers({
    ...clicks,
    ...injectedReducers,
  });

  return rootReducer;
}

export type RootState = ReturnType<typeof rootReducer>