How to use the @ionic-native/code-push.SyncStatus.ERROR function in @ionic-native/code-push

this.messageText = '安装更新 ..';
                    break;

                case SyncStatus.UPDATE_INSTALLED:
                    this.messageText = '安装更新 ..';
                    const alert = this.alertCtrl.create({
                        title: '更新',
                        message: '安装了一个新的更新，并将在下次重新启动应用程序时可用',
                        buttons: ['好']
                    });
                    alert.present();
                    alert.onDidDismiss(() => {
                    });
                    break;

                case SyncStatus.ERROR:
                    this.messageText = '发生错误 :( ...';
                    break;

                default:
                    this.messageText = '未处理的同步状态 ..';
                    break;
            }

        });
    }

.subscribe((syncStatus) => {
        switch (syncStatus) {
          case SyncStatus.CHECKING_FOR_UPDATE:
            notificationObject.text = "Checking for updates..."
            this.localNotifications.schedule(notificationObject);
            break;
          case SyncStatus.INSTALLING_UPDATE:
            notificationObject.text = "Installing update...";
            notificationObject["progressBar"] = { value: 100 };
            this.localNotifications.update(notificationObject);
            break;
          case SyncStatus.UP_TO_DATE:
          case SyncStatus.ERROR:
          case SyncStatus.UPDATE_IGNORED:
          case SyncStatus.UPDATE_INSTALLED:
            this.localNotifications.cancel(notificationObject.id);
            break;
        }
      });
  }