Translating server code to ES6 using socket.io - node.js

Question

We are complete newbies to socket.io and express. And we have followed along this tutorial to learn socket.io https://www.valentinog.com/blog/socket-react/
And now we want to translate this line of code (older style):
const index = require("./routes/index").default
to ES6, below:
import router from './routes/index'
app.use('/', router)
But it does not work for us. We get this error in the terminal.
Full server.js code here
import express from 'express'
const app = express()
import { createServer } from 'http'
const server = createServer(app)
import { Server } from "socket.io"
const io = new Server(server)
import cors from 'cors'
import router from './routes/index'
const port = process.env.PORT || 4001
app.use('/', router)
app.use(index)
app.use(cors())
app.use(express.json())
let interval
io.on("connection", (socket) => {
console.log("New client connected")
if (interval) {
clearInterval(interval)
}
interval = setInterval(() => getApiAndEmit(socket), 1000)
socket.on("disconnect", () => {
console.log("Client disconnected")
clearInterval(interval)
})
})
const getApiAndEmit = socket => {
const response = new Date()
socket.emit("FromAPI", response)
}
app.listen(port, () => {
// eslint-disable-next-line
console.log(`Server running on http://localhost:${port}`)
})

Answer 1

I was able to use socket.io on my project like so:
const app = express()
const http = require('http').createServer(app)
const socketIo = require('socket.io')(http)
In other words I used require and did not use router. This might work for you unless there is a specific reason you need to do otherwise.