You can also, if you like use socket id to manage your player list like this.
io.on('connection', function(socket){
socket.on('disconnect', function() {
console.log("disconnect")
for(var i = 0; i < onlineplayers.length; i++ ){
if(onlineplayers[i].socket === socket.id){
console.log(onlineplayers[i].code + " just disconnected")
onlineplayers.splice(i, 1)
}
}
io.emit('players', onlineplayers)
})
socket.on('lobby_join', function(player) {
if(player.available === false) return
var exists = false
for(var i = 0; i < onlineplayers.length; i++ ){
if(onlineplayers[i].code === player.code){
exists = true
}
}
if(exists === false){
onlineplayers.push({
code: player.code,
socket:socket.id
})
}
io.emit('players', onlineplayers)
})
socket.on('lobby_leave', function(player) {
var exists = false
for(var i = 0; i < onlineplayers.length; i++ ){
if(onlineplayers[i].code === player.code){
onlineplayers.splice(i, 1)
}
}
io.emit('players', onlineplayers)
})
})