Node Servers - https://riptutorial.com/node-js/example/21004/using-an-iis-virtual-directory-or-nested-application-via--appsettings-

index.html

    <script>
    // to dynamically set base url by reading the virtual servers path from the url
    // doesn't work perfectly, causes double load as the first set of script calls fire to the base / url without the vd, then the second set go to the vd url (runtime.js etc)
      let p = location.pathname.split('/').filter(x => x);
      let baseHref = '/';
      if (!location.origin.includes('localhost:4200')) {
        baseHref += p[0] + '/' + p[1] + '/' + p[2] + '/';
      }
      console.log('baseHref', baseHref);
      window['base-href'] = baseHref;
      document.write(`<base href="${window['base-href']}" />`);
    </script>

virtual-server.js

const express = require('express');
const path = require('path');
const server = express();

const port = process.env.PORT || 3000;

const rootPath = path.join(__dirname, 'dist');

// set vd path
var virtualDirPath = '/vd/myapp/';

// dist
server.use(virtualDirPath, express.static(path.join(__dirname, 'dist')));
// node_modules
server.use(virtualDirPath + 'node_modules', express.static(path.join(__dirname, 'node_modules')));

// Setup a route at the index of our app
server.get(virtualDirPath, (req, res) => {
  return res.sendFile(path.resolve(__dirname, 'dist', 'index.html'));
});

server.listen(port, () => {
  console.log(`Listening on ${port}`);
});