/**
 * @description
 * - rename filename to content hash + extname;
 * - return list of (renamed) filenames
 */
export declare function scanDir(dir: string): Promise<string[]>;
export declare function isContentHash(file_or_filename: string): boolean;
export declare function saveFile(args: {
    dir: string;
    content: Buffer;
    mimeType: string;
}): Promise<void>;
export declare function hashContent(content: Buffer, encoding?: BufferEncoding): string;
/** @returns new filename with content hash and extname */
export declare function renameFileByContentHash(file: string): Promise<string>;