code: function showLoading(cfg = {}) {
      if (_.isString(cfg)) {
          cfg = {
              data: {
                  message: cfg
              }
          };
      }
      // use default loading template if not passed as a configuration
      _.defaultsDeep(cfg, {
          template: defaults.templates.loader,
          type: 'modal'
      });
  
      console.log('showing loader... options:', cfg);
  
      // cache the doc for later use
      loaderDoc = show(cfg);
  
      return loaderDoc;
  }
docs: Shows a loading page if a loader template exists.
  Also applies any default handlers and caches the document for later use.
  
  @inner
  @alias module:navigation.showLoading
  
  @param  {Object|Function} cfg    The configuration options or the template function
  @return {Document}               The created loader document.