How to use the @grafana/data.AppEvents.alertError function in @grafana/data

while (file) {
          const reader = new FileReader();
          reader.onload = readerOnload();
          reader.readAsText(file);
          i += 1;
          file = files[i];
        }
      }

      const wnd: any = window;
      // Check for the various File API support.
      if (wnd.File && wnd.FileReader && wnd.FileList && wnd.Blob) {
        // Something
        elem[0].addEventListener('change', file_selected, false);
      } else {
        appEvents.emit(AppEvents.alertError, ['Oops', 'The HTML5 File APIs are not fully supported in this browser']);
      }
    },
  };

.catch(err => {
        if (!err.message && err.data && err.data.message) {
          err.message = err.data.message;
        }
        console.log('AnnotationSrv.query error', err);
        this.$rootScope.appEvent(AppEvents.alertError, ['Annotation Query Failed', err.message || err]);
        return [];
      });
  }

.catch(e => {
        appEvents.emit(AppEvents.alertError, ['Template variable service failed', e.message]);
      });
  }

return variableSrv.updateOptions($scope.current).catch((err: { data: { message: any }; message: string }) => {
        if (err.data && err.data.message) {
          err.message = err.data.message;
        }
        appEvents.emit(AppEvents.alertError, [
          'Templating',
          'Template variables could not be initialized: ' + err.message,
        ]);
      });
    };

.catch(err => {
        if (!err.message && err.data && err.data.message) {
          err.message = err.data.message;
        }
        console.log('AnnotationSrv.query error', err);
        this.$rootScope.appEvent(AppEvents.alertError, ['Annotation Query Failed', err.message || err]);
        return [];
      });
  }

(err: any) => {
          console.log('Script dashboard error ' + err);
          this.$rootScope.appEvent(AppEvents.alertError, [
            'Script Error',
            'Please make sure it exists and returns a valid dashboard',
          ]);
          return this._dashboardLoadFailed('Scripted dashboard');
        }
      );

const app = await getPluginSettings(pluginId).then(info => {
        const error = getAppPluginPageError(info);
        if (error) {
          appEvents.emit(AppEvents.alertError, [error]);
          this.setState({ nav: getWarningNav(error) });
          return null;
        }
        return importAppPlugin(info);
      });
      this.setState({ plugin: app, loading: false });

}

    if (err.status === 422) {
      appEvents.emit(AppEvents.alertWarning, ['Validation failed', data.message]);
      throw data;
    }

    if (data.message) {
      let description = '';
      let message = data.message;
      if (message.length > 80) {
        description = message;
        message = 'Error';
      }

      appEvents.emit(err.status < 500 ? AppEvents.alertWarning : AppEvents.alertError, [message, description]);
    }

    throw data;
  }

() => {
        this.$scope.appEvent(AppEvents.alertError, ['Unable to save playlist']);
      }
    );

() => {
        this.$scope.appEvent(AppEvents.alertError, ['Unable to delete playlist']);
        this.playlists.push(playlist);
      }
    );