import type { TimeUnit } from '../unit';
/**
 * Check if time unit is supported.
 * @param unit		String to validate as supported time unit.
 * @returns			true 	-	Provided `unit` string is a supported time unit.
 *					false	-	Provided `unit` string is not a supported time unit.
 *
 * @category Time Units
 */
export declare function timeUnitSupported(unit?: TimeUnit): unit is TimeUnit;