text: import React, { useState, useCallback } from "react";
  
  import ReactDOM from 'react-dom';
  import { BrowserRouter } from 'react-router-dom';
  import App from "./app/App"
  
  ReactDOM.render((
    <BrowserRouter>
      <App /> {/* The various pages will be displayed by the `Main` component. */}
    </BrowserRouter>
    ), document.getElementById('root')
  );