import { Level2Date, Level2Duration } from "@rr0/time";
/**
 * The `datetime` attribute of a <time> and the EDTF it comes from.
 *
 * HTML knows its own formats only: a year, month, date, local or global date and time ("2004-06-11T09:12:33.123+01:00"),
 * and durations in days, hours, minutes and seconds ("P1DT2H30M"). EDTF is richer: qualified values ("2004-~06", "~P2H"),
 * a time zone written "+01", years and months in durations. So `datetime` holds what HTML can express, and what it cannot
 * is kept as it was written in `data-edtf`, which is only set when it differs from `datetime`.
 */
export declare class HtmlDatetime {
    /**
     * Sets the attributes of a <time> element for a time.
     *
     * @param el The element to set the attributes of.
     * @param time The time the element is about.
     */
    static apply(el: HTMLElement, time: Level2Date | Level2Duration): void;
    /**
     * @return The `datetime` value that HTML can read for a time, or undefined if HTML has no equivalent.
     */
    static of(time: Level2Date | Level2Duration): string | undefined;
    protected static ofDate(date: Level2Date): string | undefined;
    protected static ofDuration(duration: Level2Duration): string | undefined;
    /**
     * @return The numeric value of a component, if it has one (not a range of values, as for unspecified digits) within bounds.
     */
    protected static value(comp: {
        value: unknown;
    } | undefined, min: number, max?: number): number | undefined;
    protected static pad(n: number): string;
    /**
     * @param minutes The time zone offset, in minutes east of UTC.
     * @return The time zone offset as HTML writes it ("Z", "+01:00").
     */
    protected static offset(minutes: number): string;
}