code: function() {
          loader.off('error');
          loader.off('progress');
          loader.off('complete');
  
          if (request) {
              request.removeEventListener('progress', progressHandler);
              request.removeEventListener('load', loadHandler);
              request.removeEventListener('error', errorHandler);
              request.removeEventListener('load', elementLoadHandler);
              request.removeEventListener('canplaythrough', elementLoadHandler);
              request.removeEventListener('load', imageBlobHandler);
          }
      }
docs: clean up