index.js:1375 Unexpected keys “dispatch”, “subscribe”, “getState”, “replaceReducer”, “liftedStore” found in preloadedState argument passed to createStore. Expected to find one of the known reducer keys instead: “app”. Unexpected keys will be ignored.

redux工具显示没有任何state状态。
请老师解答一下， 谢谢！

文件Store.js

import {createStore, applyMiddleware} from “redux”;
import thunkMiddleware from “redux-thunk”;
import rootReducer from “./modules”;

let store;
if(window.REDUX_DEVTOOLS_EXTENSION){
const composeEnhancers = window.REDUX_DEVTOOLS_EXTENSION;
store = createStore(rootReducer, composeEnhancers(applyMiddleware(thunkMiddleware)));
}else{
store = createStore(rootReducer, applyMiddleware(thunkMiddleware));
}

export default store;

文件 modules/index.js:
import { combineReducers } from “redux”;
import app from “./app”;

const rootReducer = combineReducers({
app
});

export default rootReducer;