frontend/smart-hut/src/index.js

import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';
import * as serviceWorker from './serviceWorker';
//React Router
//import { BrowserRouter, Route, Switch } from "react-router-dom";

const index = (
    <App />
  );

ReactDOM.render(
    index
    , document.getElementById('root'));
serviceWorker.unregister();