/**
 * Extracts the file extension (without the dot) from a filename.
 * @param filename - The name (or path) of the file.
 * @returns The lowercase extension (e.g. "html"), or undefined if none.
 */
export declare function getExtension(filename: string): string | undefined;
export declare function getContentType(ext: string): string;
export declare function zipFolder(reportFolder: string, zipFile: string): Promise<boolean>;