code: function triggerEvent(gesture, eventData){
        // create DOM event
        var event = ionic.Gestures.DOCUMENT.createEvent('Event');
        event.initEvent(gesture, true, true);
        event.gesture = eventData;
  
        // trigger on the target if it is in the instance element,
        // this is for event delegation tricks
        var element = this.element;
        if(ionic.Gestures.utils.hasParent(eventData.target, element)) {
          element = eventData.target;
        }
  
        element.dispatchEvent(event);
        return this;
      }
docs: trigger gesture event
  @param   {String}      gesture
  @param   {Object}      eventData
  @returns {ionic.Gestures.Instance}