export type DateFormat = "iso" | (string & {});
export interface FormatDateOptions {
    /**
     * The format to use when converting the date to a string.
     * Default is `iso`.
     */
    format?: DateFormat;
    /**
     * The locale(s) to used for dd/ddd/dddd/MMM/MMMM format
     *
     * [MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl#locales_argument).
     */
    locales?: Intl.LocalesArgument;
    /**
     * A custom function to re-modify the way to display meridiem
     *
     */
    customMeridiem?: (hours: number, minutes: number, isLowercase?: boolean, hasPeriod?: boolean) => string;
}
/**
 * Formats a date object into a string.
 *
 * @param input The date object to format.
 * @param options The options to use when formatting the date.
 * @returns The formatted date string, or `null` if the input is not a date.
 *
 * @credits
 * [vueuse](https://github.com/vueuse/vueuse/blob/main/packages/shared/useDateFormat/index.ts)
 */
export declare function formatDate(input: unknown, options?: FormatDateOptions): string | null;