/**
 * Time-related utility functions.
 */
export declare namespace DateTimeUtil {
    function getUnixEpochMillis(date?: Date): number;
    function getISODateTimeString(now?: number, excludeTimePart?: boolean): string;
    function getISODateString(date: Date, excludeTimePart?: boolean): string;
    function getHourOfTheDay(date?: Date): number;
    function getYear(date?: Date): number;
    function getMidnightDate(date?: Date): Date;
    function getMidnight(now?: number): number;
    function getSundayMidnightDate(date?: Date): Date;
    function getSundayMidnight(now?: number): number;
    function getFirstDayMidnightDate(date?: Date): Date;
    function getFirstDayMidnight(now?: number): number;
    /**
     * Returns the number of the day in the given month.
     *
     * @param today {Date} A date in the given month.
     */
    function getNumberOfDaysInMonth(today?: Date): number;
    function getNumberOfDaysForMonth(now?: number): number;
    function getNumberOfDaysForPreviousMonth(now?: number): number;
    function getNumberOfDaysForNextMonth(now?: number): number;
}