前端项目实战拾壹-pda测试平板打包为何白屏

import React from 'react';
import ReactDOM from 'react-dom/client';
import './index.css';
import App from './App';
import reportWebVitals from './reportWebVitals';
alert("first")
const root = ReactDOM.createRoot(document.getElementById('root'));
alert("second")
root.render(
  <React.StrictMode>
    <App />
  </React.StrictMode>
);
alert("third")
// If you want to start measuring performance in your app, pass a function
// to log results (for example: reportWebVitals(console.log))
// or send to an analytics endpoint. Learn more: https://bit.ly/CRA-vitals
reportWebVitals();