Socket.io Connection Keep Increasing Each Time A New Connect Has Been Made

I'm using Express4 with a router that points to path /, and that is handled by a JS file named chat.js. And my IO object is already bind to app.io, so inside my chat.js I'll call m

Solution 1:

Every time your / route is hit, you create a new duplicate io.on('connection', ...) event handler. So, after that route is hit 3 times, you have 3 event handlers for the connection event. So, when it occurs, your code gets called 3 times.

Instead, you should do the io.on('connection', ...) only once outside the route.

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FYI, you don't seem to be doing anything useful with the uid you are creating because you don't associate it with any particular connection. FYI, each socket.io connection already has a unique socket.id which is uniquely associated with each socket.io connection so that you can get the id from the socket or can retrieve the socket given only the id.