How to get OneSignal player Ids in Ionic 2

I am using onesignal plugin for an app that I am developing in Ionic 2, the plugin is working. The messages sent from OneSignal are showing in the app but I have a problem when I try to get the player unique id:

This is the code that I use for showing messages, this code works:

 let notificationOpenedCallback = function(jsonData) {
        let alert =alertCtrl.create({
          title: jsonData.notification.payload.title,
          subTitle: jsonData.notification.payload.body,
          buttons: ['OK']
        });
        alert.present();
        console.log('notificationOpenedCallback: ' + JSON.stringify(jsonData));
      };

      window["plugins"].OneSignal
        .startInit("05d411f4-45da-4101-92a5-4a60e5c9fd03", "49543248748")
        .handleNotificationOpened(notificationOpenedCallback)
        .endInit();

and this code is for get Ids:

window["plugins"].OneSignal
             .startInit("05d411f4-45da-4101-92a5-4a60e5c9fd03", "49543248748")
             .endInit();
            window["plugins"].OneSignal.getIds(function(ids){
              firebase.database().ref('usuarios/'+ this.usuarioId).update({
                idOnesignal: ids.userId
              })

this code just does not run