import { InjectionToken } from '@angular/core' ; /**
 * Optional injectable token to handle file uploads in the chat.
 */ export const FILE_UPLOAD_HANDLER_TOKEN = new InjectionToken < FileUploadHandler > ( 'ngxChatFileUploadHandler' ) ; export interface FileUploadHandler { return { string } upload ( file ) : Promise < string > ; isUploadSupported ( ) : boolean ; }