One more ws connection came from nowhere

[qiulang]

I find I can trigger an unexpected socket.io connection under some circumstance

This is my client code (4.5.2)

    const socket = io(wsServer,{
        transports: ['websocket'],
        auth:{token,uid,client}
    })
    socket.on("connect", () => {
        log(`debug 2nd connection ${socket.id}:${token}`)
        ...
    })

But from console I only see my log "debug 2nd connection" once. I can't figure out where does the 2nd connection come from!
But I find under that circumstance if I set the function which will be called to a "real" function I can make the unexpected connection disappear: e.g. I change the code from let aCB to let aCB = ()=>{} to fix it.

The aCB is a callback function my user may provide. If they don't provide it and I don't set it to noop or check it explicitly before calling it, the unexpected ws connection will show up.

But why ? Any idea ?

[darrachequesne]

Hi! Could you please provide an example reproducing the issue? You can fork the example here: https://github.com/socketio/socket.io-fiddle

Without that, I'm afraid we won't be able to track down the issue. Thanks!

[qiulang]

Yes I will try to reproduce the issue based on https://github.com/socketio/socket.io-fiddle

[qiulang]

@darrachequesne when try to reproduce this problem, I hit another error, can you take a look darrachequesne/notepack#29 ?

I have hit the problem with admin-ui before socketio/socket.io-admin-ui#48

I have not been able to reproduce my problem based on a simple project template like https://github.com/socketio/socket.io-fiddle. I think that is because my problem involved with webpack bundled code. Without that I can't reproduce the problem, but webpack setting is just beyond me. 😅