NodeJs - Socket connection

index.js

var fs = require('fs');
var net = require('net');
var server = net.createServer(function(c) { //'connection' listener
    console.log('server connected');
    c.on('end', function() {
        console.log('server disconnected');
    });
    c.write('hello\r\n');
    c.pipe(c);
});

server.on('error', function (e) {
    if (e.code == 'EADDRINUSE') {
        var clientSocket = new net.Socket();
        clientSocket.on('error', function(e) { // handle error trying to talk to server
            if (e.code == 'ECONNREFUSED') {  // No other server listening
                fs.unlinkSync('/tmp/app-monitor.sock');
                server.listen('/tmp/app-monitor.sock', function() { //'listening' listener
                    console.log('server recovered');
                });
            }
        });
        clientSocket.connect({path: '/tmp/app-monitor.sock'}, function() { 
            console.log('Server running, giving up...');
            process.exit();
        });
    }
});

server.listen('/tmp/app-monitor.sock', function() { //'listening' listener
    console.log('server bound');
});

from this stackoverflow