Reactjs &引用；React.createElement:类型无效"；使用ConnectedRouter时

代码是一个演示水疗中心，有两条路线（回家和柜台）。为什么捆绑时使用

ConnectedRouter

会发出以下警告，而使用

BrowserRouter

则可以正常工作

Warning: React.createElement: type is invalid -- expected a string (for built-in components) or a class/function (for composite components) but got: undefined. You likely forgot to export your component from the file it's defined in. Check the render method of `Unknown`.
in Unknown
in AppContainer

App.jsx

import React from 'react';
import { createStore, combineReducers, applyMiddleware } from 'redux';
import { Provider } from 'react-redux';
import { Route } from 'react-router-dom';
import { ConnectedRouter, routerReducer, routerMiddleware } from 'react-router-redux';
import createHistory from 'history/createBrowserHistory';

import Counter from './containers/Counter';
import countReducer from './reducers';

const history = createHistory();

const store = createStore(
  combineReducers({
    count: countReducer,
    router: routerReducer
  },
  applyMiddleware(
    routerMiddleware(history)
  )
);

export default () => (
  <Provider store={store}>
    <ConnectedRouter history={history}>
      <div>
        <Route exact path="/" render={() => <h1>Hello, World!</h1>} />
        <Route path="/counter" component={Counter} />
      </div>
    </ConnectedRouter>
  </Provider>
);

import React from 'react';
import ReactDOM from 'react-dom';

import App from './App';

const render = (Component) => {
  ReactDOM.render(
    Component,
    document.getElementById('root')
  );
};

if (process.env.NODE_ENV === 'production') {
  render(<App />);
} else {
  const { AppContainer } = require('react-hot-loader');

  render(
    <AppContainer>
      <App />
    </AppContainer>
  );

  if (module.hot) {
    module.hot.accept('./App', () => {
      const NextApp = require('./App').default;

      render(
        <AppContainer>
          <NextApp />
        </AppContainer>
      );
    });
  }
}

从“React”导入React；
从'redux'导入{createStore，combinereducer，applyMiddleware}；
从'react redux'导入{Provider}；
从'react router dom'导入{Route}；
从“react router redux”导入{ConnectedRouter，routerReducer，routerMiddleware}；
从“历史记录/createBrowserHistory”导入createHistory；
从“./集装箱/柜台”导入柜台；
从“./reducers”导入countReducer；
const history=createHistory（）；
const store=createStore(
组合传感器({
count:countReducer，
路由器：路由器导出器
},
applyMiddleware(
路由器管理软件（历史记录）
)
);
导出默认值（）=>(
你好，世界！}/>
);

index.jsx

import React from 'react';
import { createStore, combineReducers, applyMiddleware } from 'redux';
import { Provider } from 'react-redux';
import { Route } from 'react-router-dom';
import { ConnectedRouter, routerReducer, routerMiddleware } from 'react-router-redux';
import createHistory from 'history/createBrowserHistory';

import Counter from './containers/Counter';
import countReducer from './reducers';

const history = createHistory();

const store = createStore(
  combineReducers({
    count: countReducer,
    router: routerReducer
  },
  applyMiddleware(
    routerMiddleware(history)
  )
);

export default () => (
  <Provider store={store}>
    <ConnectedRouter history={history}>
      <div>
        <Route exact path="/" render={() => <h1>Hello, World!</h1>} />
        <Route path="/counter" component={Counter} />
      </div>
    </ConnectedRouter>
  </Provider>
);

import React from 'react';
import ReactDOM from 'react-dom';

import App from './App';

const render = (Component) => {
  ReactDOM.render(
    Component,
    document.getElementById('root')
  );
};

if (process.env.NODE_ENV === 'production') {
  render(<App />);
} else {
  const { AppContainer } = require('react-hot-loader');

  render(
    <AppContainer>
      <App />
    </AppContainer>
  );

  if (module.hot) {
    module.hot.accept('./App', () => {
      const NextApp = require('./App').default;

      render(
        <AppContainer>
          <NextApp />
        </AppContainer>
      );
    });
  }
}

从“React”导入React；
从“react dom”导入react dom；
从“./App”导入应用程序；
常量渲染=（组件）=>{
ReactDOM.render(
组成部分，
document.getElementById（'root'））
);
};
if（process.env.NODE_env===‘生产’）{
render（）；
}否则{
const{AppContainer}=require（'react-hot-loader'）；
渲染(
);
如果（模块热）{
module.hot.accept（'./App'，（）=>{
const nextap=require（'./App'）。默认值；
渲染(
);
});
}
}

显示AppContainer组件。@安德鲁：你能详细说明一下吗？我也尝试在顶部导入它，但结果相同。我错过了AppContainer是hotloader组件。我认为这是自定义的。我不确定哪里有问题。如果你改为

导出默认值（）=>（测试）

您会有错误吗？问题在完全重写后得到解决。不知道我遗漏了什么。