code: function MdBottomSheetDirective($mdBottomSheet) {
    return {
      restrict: 'E',
      link : function postLink(scope, element) {
        element.addClass('_md');     // private md component indicator for styling
  
        // When navigation force destroys an interimElement, then
        // listen and $destroy() that interim instance...
        scope.$on('$destroy', function() {
          $mdBottomSheet.destroy();
        });
      }
    };
  }
docs: /* @ngInject