import type { Time } from '../time';
import type { TimeUnit } from './unit';
/**
 * Time remaining until `time`. Negative when `time` is already in the past.
 * Numbers are interpreted as a unix timestamp in seconds. The returned Time
 * uses `units` (defaults to seconds). Returns null when input is invalid or
 * the computed result falls outside the safe integer range.
 *
 * @param time		Target Time instance, or unix timestamp in seconds.
 * @param units		Units for the returned Time. Defaults to `'s'`.
 */
export declare function timeUntil(time: Time | number, units?: TimeUnit): Time | null;