🚨 Socket.io WebSocket Connection Issue (Need Help Debugging)

Hey Folks 👋

I’m facing a frustrating issue while working with Socket.io (client-side using socket.io-client) in my project. Here's the setup and the exact problem I'm dealing with:

✅ Context:

I'm using socket.io-client to connect to a WebSocket server (localhost:4000) via a wrapper utility:

```

import { io, Socket } from "socket.io-client";

let socket: Socket | null = null;

export const connectSocket = (token: string): Socket => {

if (!socket) {

socket = io("http://localhost:4000/", {

transports: ["websocket"],

auth: { token },

});

socket.on("connect", () => console.log("✅ Socket connected"));

socket.on("connect_error", (err) =>

console.error("❌ Socket connection error:", err)

);

}

return socket;

};

```

❌ The Issues:

WebSocket fails to connect initially

I get this error in the browser console:

```

WebSocket connection to 'ws://localhost:4000/socket.io/?EIO=4&transport=websocket' failed:

WebSocket is closed before the connection is established.

```

**Messages are received only after switching tabs**

Even when the client emits messages, the listener doesn't pick them up in real-time. Oddly enough, the messages appear only when I switch tabs (i.e., the browser seems to "wake up" the tab and events get flushed).

🔍 What I suspect:

Possibly a CORS or handshake timing issue?
Something to do with how the event loop is managed in inactive tabs?
Or maybe transports: ['websocket'] is causing premature closure?

❓What I’m Looking For:

Has anyone faced this WebSocket + tab-switch + delayed message reception combo?
Any recommended fixes or debugging pointers for both connection failure and delayed message receipt?
Could this be server-side misconfiguration?

Thanks in advance 🙏

0 comments

🚨 Socket.io WebSocket Connection Issue (Need Help Debugging)

The AI Overtake

skool.com/tech-masters-institution-4806

Turn code into cash 💰

Get hired by Big Tech, or build your own AI startup.

With AI, build any idea in minutes.

Become an AI Master.

Start today.

Leaderboard (30-day)