import React from 'react';
import ReactDOM from 'react-dom';
import { BrowserRouter as Router, Route, Redirect } from 'react-router-dom';

const PrivateRoute = ({ component: Component, ...rest }) => (
  <Route
    {...rest}
    render={props =>
      isLoggedIn() ? (
        <Component {...props} />
      ) : (
        <Redirect to="/login" />
      )
    }
  />
);

const Login = () => {
  // 处理登录逻辑
  return (
    // 登录表单
  );
};

const App = () => (
  <Router>
    <div>
      <Route path="/login" component={Login} />
      <PrivateRoute path="/dashboard" component={Dashboard} />
    </div>
  </Router>
);

ReactDOM.render(<App />, document.getElementById('root'));