Is this Express + HTTPS spdy + socket.io server correctly initialized?

Question

I've been working on a project a while and I'm not sure that my https is correctly mounted since I'm not fully aware of the sentences that are invoked in the code, could someone bring some light into this?

const express = require('express')
const spdy = require('spdy')
const cors = require('cors')
const fs = require('fs')

const app = express()

const serverCertificates = {
  key: fs.readFileSync(__dirname + '/cfg/cert/localhost-private.pem'),
  cert: fs.readFileSync(__dirname + '/cfg/cert/localhost-cert.pem')
}

const corsOptions = {
  cors: {
    origin: "https://localhost:3200",
    transports: ['websocket'],
    upgrade: false
  }
}
    

Up to here is just require, mounting express on app and declaring some server options

After the classic app.use statements comes the trouble, I need to run HTTPS and Socket.io in the same server, and the only role that express is doing is serving statics directories

app.use(express.json())
app.use(cors())
app.use('/', express.static('./public'))
app.get('/favico.ico', (req, res) => res.sendFile(__dirname + '/public/favico.ico'))



let server = spdy.createServer(serverCertificates, app)
let io = app.io = require('socket.io')(server, corsOptions)
io.attach(server)

server.listen(3200, (error) => {
  if (error) {
    return process.exit(1)
  } else {
    console.log('Escuchando en *:' + PORT)
  }
})

server.on('error', err => console.log(err))

Now I'm not using express routing as an API because the communication with client is done by Express.IO but eventually the project must contain a database that would be handled by express.

The question is "am I doing the right things here? is there a better way of mounting this type of server?"

Thanks in advance