/**
 * Parses `CronHours` into a string.
 *
 * @category Parsers
 * @example
 * ```typescript
 * parseCronHours(10); // "10"
 * parseCronHours("*"); // "*"
 * parseCronHours({ every: 10, start: 2 }); // "2/10"
 * parseCronHours([1, 2, 3, 4]); // "1,2,3,4"
 * parseCronHours({ from: 5, to: 10 }); // "5-10"
 * parseCronHours([1, 2, 3, 4, { from: 5, to: 10 }]); // "1,2,3,4,5-10"
 * ```
 * @param source `CronHours` to be parsed.
 * @returns A string or `undefined` if invalid.
 */
export declare const parseCronHours: (
	source:
		| "*"
		| import("../index.js").CronHoursValue
		| import("../index.js").CronList<import("../index.js").CronHoursValue>
		| import("../index.js").CronRange<import("../index.js").CronHoursValue>
		| import("../index.js").CronSteps<import("../index.js").CronHoursValue>,
) => import("@vangware/types").Maybe<string>;