New to node.js and struggling with socket.io

#webrtc #node #webdev #javascript

Hi all,

Nervous first post but really need some help. I'm working on a Web application for p2p communication (both video and text).

The video communication works (some teething issues), but my main issue is getting user socket.id. specifically the user just having connected.

I have tried many things including:
Socket.on("connected", () {
console.log(socket.id);
});

All I get is "undefined". Yet if I run te same console.log code after the page loads I can get it displayed.

Not sure how to work with that.

I want to store the socket.id and username in an object/array

Thank you

Top comments (7)

peerreynders • Jul 9 '21 • Edited

socket.on(eventName, listener)
Socket#id
How does that work?

Watch for the casing on the variable names:

// 1. "socket" all lowercase
const socket = io("ws://localhost:3000");

// 2. "socket" all lowercase
socket.on("connect", () => {
  // 3. "socket" all lowercase
  console.log(socket.id);
});

Basically the listener is a function expression (arrow functions are always function expressions) - and a function has access to all the variables in the scope that created it (in this case socket).

MDN: Closures

A function declaration

const socket = io("ws://localhost:3000");

socket.on("connect", connectListener);

// function declaration...
function connectListener() {
  // ...also has access to the enclosing scope
  console.log(socket.id);
}