Check server status (Node)

Check.js

//npm install bluebird
//npm install net

var net = require('net');
var Promise = require('bluebird');

function checkConnection(host, port, timeout) {
    return new Promise(function(resolve, reject) {
        timeout = timeout || 10000;     // default of 10 seconds
        var timer = setTimeout(function() {
            reject("timeout");
            socket.end();
        }, timeout);
        var socket = net.createConnection(port, host, function() {
            clearTimeout(timer);
            resolve();
            socket.end();
        });
        socket.on('error', function(err) {
            clearTimeout(timer);
            reject(err);
        });
    });
}

checkConnection("localhost", 4200).then(function() {
    // successful
    console.log("Server is running");
}, function(err) {
    console.log("Server is not running");
    // error
})