/**
 * Format a date object as a string in the specified format.
 * @param date The date object to format.
 * @param format The format string (e.g., 'YYYY-MM-DD HH:mm:ss').
 * @returns The formatted date string.
 */
export declare function formatDate(date: Date, format: string): string;
/**
 * Get the current date and time formatted as a string in the specified format.
 * @param format The format string (e.g., 'YYYY-MM-DD HH:mm:ss').
 * @returns The formatted current date and time string.
 */
export declare function getCurrentDateTime(format: string): string;
/**
 * Parse a date string into a Date object.
 * @param dateString The date string to parse.
 * @returns The parsed Date object, or null if parsing fails.
 */
export declare function parseDate(dateString: string): Date | null;
/**
 * Check if a given year is a leap year.
 * @param year The year to check.
 * @returns True if the year is a leap year, false otherwise.
 */
export declare function isLeapYear(year: number): boolean;