Cannot read properties of undefined (reading 'protocol')

[DAVIGALEE]

After setting up the project and running with "npm start" in terminal, the error comes up and saying that protocol is not defined in socket.js. I tried to set up project in a new folder but same thing keeps popping up. \node_modules\socket.io\dist\socket.js:44 if (client.conn.protocol === 3) { ^ TypeError: Cannot read properties of undefined (reading 'protocol')

[darrachequesne]

Hi!

The issue seems to come from this line: https://github.com/socketio/socket.io/blob/134226e96cfacab300ab8f27cf5765d5b07d0271/lib/socket.ts#L165

That being said, I don't think how client.conn can be undefined there. Which version of socket.io/Node.js are you using?

[DAVIGALEE]

I have installed the latest version of socket.io

[tandv592082]

I have installed the latest version of socket.io

Hi, may be you aren't handle socket middleware like:

io.use((socket, next) => {
  const {name, age} = socket.handshake.auth;

  if(name) {
    socket.name = name;
  }

  if(age) {
   socket.age = age;
  }

  next()
})

Expected:

io.use((socket, next) => {
  const {name, age} = socket.handshake.auth;

  if(!name || !age) {
    return next();
  }

  if(age) {
   socket.age = age;
   return next();
  } 

 socket.name = name;
  next()
})

[tulburg]

Having same issue after switching to ES Module from commonjs

this fixed it for me

import * as Socket from 'socket.io';

[darrachequesne]

@tulburg I don't think this is related to the issue here, as both CommonJS and ES modules are supported.

I'm going to close this issue, as we were unable to reproduce it.

[Lokesh396]

This code is from the documentation and it is working fine. `import { createServer } from "http"; import { Server } from "socket.io";

const httpServer = createServer(); const io = new Server(httpServer, { /* options */ });

io.on("connection", (socket) => { // ... });

httpServer.listen(3000);`