[vic5710]

рабочий пример

var clients = 0;
io.on('connection', (socket) => {
	 clients++;
	 console.log('connect: '+ clients);
	 socket.emit('news',{value: 'connect: '+ clients}); //to client
	 io.sockets.emit('news',{value: 'Hi all !'});// to all
     socket.on('disconnect', () => {
	 clients--;
	 console.log('disconnect: '+ clients);
    });
	socket.on('error', (err) => {
	    console.log(err);
	});
});