Ionic 2 Push notification error

I wrote an article to explain push notifications for both iOS and Android. See if that's useful Ionic 2 Push Notifications

Right now, I couldn't find any documentation on Ionic 2 website for Push notification. But using this link Ionic 2 Push and Phonegap plugin push, I am able to get basic notifications at least on android.

I have following code in my MainApp constructor

 constructor(platform:Platform, private app:IonicApp) {
        platform.ready().then(() => {
            StatusBar.styleDefault();
        });

        var push = Push.init({
            android: {
                senderID: "YOUR_SENDER_ID"
            },
            ios: {
                alert: "true",
                badge: true,
                sound: 'false'
            },
            windows: {}
        });

        push.on('registration', (data) => {
            console.log("registraiton id " + data.registrationId);
        });

        push.on('notification', (data) => {
            console.log(data.message);
            console.log(data.title);
            console.log(data.count);
            console.log(data.sound);
            console.log(data.image);
            console.log(data.additionalData);
        });

        push.on('error', (e) => {
            console.log(e.message);
        });

}

And on server side, I am using following code for push notification

var express = require('express');
var gcm = require('node-gcm');
var app = express();
var gcmApiKey = 'YOUR_GCM_API_KEY'; // GCM API KEY OF YOUR GOOGLE CONSOLE PROJECT

var server = app.listen(3000, function () {
    console.log('server is just fine!');
});

app.get('/', function (req, res) {
    res.send("This is basic route");
});

app.get('/push', function (req, res) {
    var device_tokens = []; //create array for storing device tokens

    var retry_times = 4; //the number of times to retry sending the message if it fails
    var sender = new gcm.Sender(gcmApiKey); //create a new sender
    var message = new gcm.Message(); //create a new message
    message.addData('title', 'PushTitle');
    message.addData('message', "Push message");
    message.addData('sound', 'default');
    message.collapseKey = 'Testing Push'; //grouping messages
    message.delayWhileIdle = true; //delay sending while receiving device is offline
    message.timeToLive = 3; //number of seconds to keep the message on
    //server if the device is offline

    //Take the registration id(lengthy string) that you logged
    //in your ionic v2 app and update device_tokens[0] with it for testing.
    //Later save device tokens to db and
    //get back all tokens and push to multiple devices
    device_tokens[0] = "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX";
    sender.send(message, device_tokens[0], retry_times, function (result) {
        console.log('push sent to: ' + device_tokens);
        res.status(200).send('Pushed notification ' + device_tokens);
    }, function (err) {
        res.status(500).send('failed to push notification ');
    });
});

I started a thread Ionic 2 Push Thread on Ionic website for Push notification document, if you want, you can follow that thread.

Steps to run the server. On OS X, you might need to run following commands with sudo.

• Download Nodejs from NodeJs. It will install node and npm in your system.
• npm install express-generator -g
• express MySampleApp
• cd MySampleApp
• npm install --save node-gcm
• npm install
• Change contents of app.js with above server code and then run server using following command
• node app.js