如何正确地在部署中使用create-react-app和expressjs后端进行api调用？

npx create-react-app my-app

npm init -y

npm install express body-parser cors

const express = require('express');
const bodyParser = require('body-parser');
const cors = require('cors');

const app = express();
app.use(bodyParser.json());
app.use(cors());

app.get('/api/data', (req, res) => {
  const data = { message: 'Hello from the backend!' };
  res.json(data);
});

const port = process.env.PORT || 5000;
app.listen(port, () => {
  console.log(`Server is running on port ${port}`);
});

import React, { Component } from 'react';

class App extends Component {
  componentDidMount() {
    fetch('/api/data')
      .then(response => response.json())
      .then(data => console.log(data))
      .catch(error => console.log(error));
  }

  render() {
    return (
      <div>
        <h1>Hello, World!</h1>
      </div>
    );
  }
}

export default App;

npm run build

npm install -g pm2
pm2 start server.js --name my-app