esponse.json().then(function(articles) {
                    articles.forEach(function(article) {
                      fuse.add(article);
                    });
                  })
                } else {
                  return Promise.reject(
                    new Error('Unexpected status from search index request: ' +
                              response.status)
                  );
                }
              });
            })).then(function() {
              return fuse;
            });
 