import React from 'react';
import ReactDOM from 'react-dom';
import { createStore } from 'redux';
import  createHistory  from 'history/createBrowserHistory';
import { Provider } from 'react-redux';
import  ConnectedRouter  from 'react-router-redux';
import { Route, Switch } from 'react-router';
import Home from "./pages/Home";
import Register from "./pages/Register";
import CourseManagerDashboard from "./pages/CourseManagerDashboard";
import CourseDetail from "./pages/CourseDetail";
import App from './app/App';
import LoginForm from './components/LoginForm';

const store = createStore(
    state => state
);
const history = createHistory();

ReactDOM.render((
    <Provider store={store}>
        <ConnectedRouter history={history}>
            <Switch>
                <Route name="home" exact path="/" component={Home} />
                <Route name="register" path="/register" component={Register} />
                <Route name="course-manager-dashboard" path="/course-manager-dashboard" component={CourseManagerDashboard} />
                <Route name="course-detail" path="/course-detail" component={CourseDetail} />
                <Route name="login" path="/login" component={LoginForm} />
                <Route path="/" component={App} />
            </Switch>
        </ConnectedRouter>
    </Provider>
),document.getElementById('app'));

获取以下错误：
元素类型无效：应为字符串（对于内置组件）或类/函数（对于复合组件），但得到：未定义。您可能忘记从定义组件的文件中导出组件，或者您可能混淆了默认导入和命名导入。无法跟踪问题的确切位置。