/**
 * Return the extension of the `path` with leading period.
 * @param path with extension
 * @returns extension (ex. for `file.ts` returns `.ts`)
 */
export declare function posixExtname(path: string): string;
/**
 * Return the extension of the `path` with leading period.
 * @param path with extension
 * @returns extension (ex. for `file.ts` returns `.ts`)
 */
export declare function windowsExtname(path: string): string;