/**
 * Formats a single-digit number as a two-digit string with a leading zero.
 * @param {number} num - The number to format.
 * @returns {string} The formatted two-digit string.
 */
export declare const padTo2Digits: (num: number) => string;
/**
 * Checks if a given string matches the ISO 8601 basic date format (YYYY-MM-DD).
 * @param {string | null | undefined} date - The date string to check.
 * @returns {boolean} True if the string matches the format, false otherwise.
 */
export declare const dateMatchIso: (date: string | null | undefined) => boolean;
/**
 * Checks if a given string matches the French date format (DD/MM/YYYY).
 * @param {string | null | undefined} date - The date string to check.
 * @returns {boolean} True if the string matches the format, false otherwise.
 */
export declare const dateMatchFrIso: (date: string | null | undefined) => boolean;
/**
 * Parses a string in the format 'YYYY-MM-DD' into an array of year, month, and day strings.
 * @param {string} date - The date string to parse.
 * @returns {string[]} An array containing [year, month, day].
 */
export declare const parseDate: (date: string) => (string | undefined)[];
/**
 * Parses a string in the format 'DD/MM/YYYY' into an array of year, month, and day strings.
 * @param {string} date - The date string to parse.
 * @returns {string[]} An array containing [day, month, year].
 */
export declare const parseDateToFr: (date: string) => (string | undefined)[];
/**
 * Formats a date string in the ISO 8601 basic format (YYYY-MM-DD) to the French format (DD/MM/YYYY).
 * @param {string} date - The date string to format.
 * @returns {string} The formatted date string in French format, or an empty string if invalid input is provided.
 */
export declare const dateToFormatFr: (date: string) => string;
/**
 * Formats a date string in the French format (DD/MM/YYYY) to the ISO 8601 basic format (YYYY-MM-DD).
 * @param {string} date - The date string to format.
 * @returns {string} The formatted date string in French format, or an empty string if invalid input is provided.
 */
export declare const dateToBasicFormat: (date: string) => string;
/**
 * Converts a string value in the ISO 8601 basic format (YYYY-MM-DD) to a JavaScript Date object.
 * @param {string} value - The string value to convert.
 * @returns {Date | undefined} A Date object representing the date, or undefined if the string is not in valid format.
 */
export declare const stringToDate: (value: string) => Date | undefined;