/**
 * Extracts and returns the date portion of a Date object as a string in YYYY-MM-DD format.
 *
 * @example
 * extractDate(new Date("2024-01-25T14:30:00")) // "2024-01-25"
 *
 * @param date The date to extract from.
 * @returns The date string.
 */
export declare function extractDate(date?: Date | string | number | null): string;