title: paho mqtt javascript client cannot subscribe to a topic
body: <blockquote>
    <p>AMQJS0005E Internal error. Error Message: Cannot read property 'subscribe' of undefined</p>
  </blockquote>
  
  <p>I included eclipse paho javascript client library in my app.
  connection is established but, I cannot subscribe to a topic.
  here is the code that I used..</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>import { Component } from '@angular/core';
  import { NavController, NavParams ,MenuController } from 'ionic-angular';
  import { Setuser } from '../../providers/setuser';
  import { Platform } from 'ionic-angular';
  import { Paho} from 'ng2-mqtt/mqttws31';
  /*
    Generated class for the Usershome page.
  
    See http://ionicframework.com/docs/v2/components/#navigation for more info on
    Ionic pages and navigation.
  */
  @Component({
    selector: 'page-usershome',
    templateUrl: 'usershome.html'
  })
  export class UsershomePage {
    client :any;
    message :any;
  
    constructor(public navCtrl: NavController, public navParams: NavParams,public menu:MenuController,public setUserProvider: Setuser,public platform:Platform) {
     this.menu.open(); 
      
    }
    
  
    ionViewDidLoad() {
     this.menu.enable(true);
      console.log('ionViewDidLoad UsershomePage');
    }
    exitApp(){
    console.log("----------");
    this.platform.exitApp();
    }
    connectToMqtt(){
    this.client = new Paho.MQTT.Client("test.mosquitto.org",8080,"abc");
  
  // set callback handlers
  this.client.onConnectionLost = this.onConnectionLost;
  this.client.onMessageArrived = this.onMessageArrived;
  
  // connect the client
  this.client.connect({onSuccess:this.onConnect});
  }
  
  // called when the client connects
   onConnect() {
    // Once a connection has been made, make a subscription and send a message.
    console.log("onConnect");
    this.client.subscribe("mitsuruog");
    this.message = new Paho.MQTT.Message("Hello");
    this.message.destinationName = "World";
    this.client.send(this.message);
  }
  
  // called when the client loses its connection
   onConnectionLost(responseObject) {
    if (responseObject.errorCode !== 0) {
      console.log("onConnectionLost:"+responseObject.errorMessage);
    }
  }
  
  // called when a message arrives
   onMessageArrived(message) {
    console.log("onMessageArrived:"+message.payloadString);
  }
    
    
  
   
  
  }</code></pre>
  </div>
  </div>
  </p>