code: function noWrapper() {
        var noWrapper = this.slim && !this.transition;
  
        if (noWrapper && this.children().length > 1) {
          console.warn('[portal-vue]: PortalTarget with `slim` option received more than one child element.');
        }
  
        return noWrapper;
      }
docs: can't be a computed prop because it has to "react" to this.children().