如何从其他包导入子路由

// 子路由文件（subRouter.js）
const express = require('express');
const subRouter = express.Router();

subRouter.get('/', (req, res) => {
  res.send('这是子路由的首页');
});

module.exports = subRouter;

// 主应用程序文件（app.js）
const express = require('express');
const app = express();

const subRouter = require('./subRouter');
app.use('/parent', subRouter);

app.listen(3000, () => {
  console.log('应用程序已启动');
});

// 子路由文件（SubRouter.js）
import React from 'react';
import { Route, Switch } from 'react-router-dom';

import SubPage1 from './SubPage1';
import SubPage2 from './SubPage2';

const SubRouter = () => {
  return (
    <Switch>
      <Route path="/sub/page1" component={SubPage1} />
      <Route path="/sub/page2" component={SubPage2} />
    </Switch>
  );
};

export default SubRouter;

// 主应用程序文件（App.js）
import React from 'react';
import { BrowserRouter as Router, Route } from 'react-router-dom';

import SubRouter from './SubRouter';

const App = () => {
  return (
    <Router>
      <Route path="/parent" component={SubRouter} />
    </Router>
  );
};

export default App;