Configuring the redux store and Injecting Async Redux Reducers

configureStore.ts

export function injectAsyncReducer(store, name, asyncReducer) {
  if (store.asyncReducers[name]) {
    return;
  }
  store.asyncReducers[name] = asyncReducer;
  store.replaceReducer(createReducer(store.asyncReducers));
}

export const configureStore = (initialState: AppState) => {
  const enhancer = compose(applyMiddleware(...getMiddleware()));
  const store: any = createStore(createReducer(), initialState, enhancer);
  store.asyncReducers = {};
  return store;
};


const createReducer = (asyncReducers = {}) => {
    return combineReducers({
        user,
        sidenav,
        navigation,
        //...
        ...asyncReducers
    });
};