/**
 * Converts javascript date object or timestamp in milliseconds
 * to Unix timestamp.
 *
 * @hidden
 *
 * @param {Date | number} date - The date or timestamp to convert.
 * @returns {number}
 */
export declare function getUnixTimestamp(date: Date | number): number;
/**
 * Adds the given number of seconds to the given date.
 *
 * @hidden
 *
 * @param {Date | number} date - The date to add seconds to.
 * If `date` is a `number` it is treated as a timestamp in milliseconds.
 * @param {number} seconds - The number of seconds to add.
 * @returns {Date} - The new date.
 */
export declare function addSeconds(date: Date | number, seconds: number): Date;