How to use the vis-util.getAbsoluteTop function in vis-util

Timeline.prototype.getEventProperties = function (event) {
  var clientX = event.center ? event.center.x : event.clientX;
  var clientY = event.center ? event.center.y : event.clientY;
  var x;
  if (this.options.rtl) {
    x = util.getAbsoluteRight(this.dom.centerContainer) - clientX;
  } else {
    x = clientX - util.getAbsoluteLeft(this.dom.centerContainer);
  }
  var y = clientY - util.getAbsoluteTop(this.dom.centerContainer);

  var item  = this.itemSet.itemFromTarget(event);
  var group = this.itemSet.groupFromTarget(event);
  var customTime = CustomTime.customTimeFromTarget(event);

  var snap = this.itemSet.options.snap || null;
  var scale = this.body.util.getScale();
  var step = this.body.util.getStep();
  var time = this._toTime(x);
  var snappedTime = snap ? snap(time, scale, step) : time;

  var element = util.getTarget(event);
  var what = null;
  if (item != null)                                                    {what = 'item';}
  else if (customTime != null)                                         {what = 'custom-time';}
  else if (util.hasParent(element, this.timeAxis.dom.foreground))      {what = 'axis';}

getPointer(touch) {
    return {
      x: touch.x - util.getAbsoluteLeft(this.canvas.frame.canvas),
      y: touch.y - util.getAbsoluteTop(this.canvas.frame.canvas)
    };
  }

Range.prototype.getPointer = function (touch, element) {
  if (this.options.rtl) {
    return {
      x: util.getAbsoluteRight(element) - touch.x,
      y: touch.y - util.getAbsoluteTop(element)
    };
  } else {
    return {
      x: touch.x - util.getAbsoluteLeft(element),
      y: touch.y - util.getAbsoluteTop(element)
    };
  }
};