/**
 * @description Returns human-readable relative time since the date. This code is inspired by ps.
 * @param since - The date to calculate the time since
 * @returns The human-readable relative time since the date
 * @example
 * const date = new Date()
 * date.setHours(date.getHours() - 1)
 *
 * ago(date)
 *
 * // returns
 *
 * '(~ 1h ago)'
 */
export declare function ago(since: Date): string;