code: function handler(e) {
        if (!vNode.context) return
  
        // some components may have related popup item, on which we shall prevent the click outside event handler.
        var elements = e.path || (e.composedPath && e.composedPath())
        elements && elements.length > 0 && elements.unshift(e.target)
        
        if (el.contains(e.target) || isPopup(vNode.context.popupItem, elements)) return
  
        el.__vueClickOutside__.callback(e)
      }
docs: Define Handler and cache it on the element