Alertify not working with Ember transitions from route

I am trying to use alertify confirmation box when someone tries to navigate from the page. But in the willTransition action of the route, alertify is very asynchronous, and ember doesn't wait for the confirmation. No matter what you click, the page is already navigated.

willTransition(transition) {
  alertify.confirm('Confirm', 'Are you sure you want to navigate?', function(e) {
    if(e) {
     return true;
    } else {
     transition.abort();
    }
  });
}

Please help me with this!!