code: function getUserInstalledExtensions() {
          var result = new $.Deferred();
  
          if (!ExtensionManager.hasDownloadedRegistry) {
              ExtensionManager.downloadRegistry().done(function () {
                  result.resolve(getUserExtensionsPresentInRegistry(ExtensionManager.extensions));
              })
                  .fail(function () {
                      result.resolve([]);
                  });
          } else {
              result.resolve(getUserExtensionsPresentInRegistry(ExtensionManager.extensions));
          }
  
          return result.promise();
      }
docs: Utility function to get the user installed extension which are present in the registry