code: function getBoundingClientRect(element) {
      var rect = {}; // IE10 10 FIX: Please, don't ask, the element isn't
      // considered in DOM in some circumstances...
      // This isn't reproducible in IE10 compatibility mode of IE11
  
      try {
        if (isIE(10)) {
          rect = element.getBoundingClientRect();
          var scrollTop = getScroll(element, 'top');
          var scrollLeft = getScroll(element, 'left');
          rect.top += scrollTop;
          rect.left += scrollLeft;
          rect.bottom += scrollTop;
          rect.right += scrollLeft;
        } else {
          rect = element.getBoundingClientRect();
        }
      } catch (e) {}
  
      var result = {
        left: rect.left,
        top: rect.top,
        width: rect.right - rect.left,
        height: rect.bottom - rect.top
      }; // subtract scrollbar size from sizes
  
      var sizes = element.nodeName === 'HTML' ? getWindowSizes(element.ownerDocument) : {};
      var width = sizes.width || element.clientWidth || result.right - result.left;
      var height = sizes.height || element.clientHeight || result.bottom - result.top;
      var horizScrollbar = element.offsetWidth - width;
      var vertScrollbar = element.offsetHeight - height; // if an hypothetical scrollbar is detected, we must be sure it's not a `border`
      // we make this check conditional for performance reasons
  
      if (horizScrollbar || vertScrollbar) {
        var styles = getStyleComputedProperty(element);
        horizScrollbar -= getBordersSize(styles, 'x');
        vertScrollbar -= getBordersSize(styles, 'y');
        result.width -= horizScrollbar;
        result.height -= vertScrollbar;
      }
  
      return getClientRect(result);
    }
docs: Get bounding client rect of given element
  @method
  @memberof Popper.Utils
  @param {HTMLElement} element
  @return {Object} client rect