@hebcal/hdate/dist/esm/anniversary.d.ts

converts between Hebrew and Gregorian dates using Rata Die (R.D.) algorithm by Dershowitz and Reingold

import { SimpleHebrewDate } from './hdateBase';
export type AnniversaryDate = Date | SimpleHebrewDate | number;
/**
 * Calculates yahrzeit.
 * `hyear` must be after original `date` of death.
 * Returns `undefined` when requested year preceeds or is same as original year.
 *
 * Hebcal uses the algorithm defined in "Calendrical Calculations"
 * by Edward M. Reingold and Nachum Dershowitz.
 *
 * The customary anniversary date of a death is more complicated and depends
 * also on the character of the year in which the first anniversary occurs.
 * There are several cases:
 *
 * * If the date of death is Marcheshvan 30, the anniversary in general depends
 *   on the first anniversary; if that first anniversary was not Marcheshvan 30,
 *   use the day before Kislev 1.
 * * If the date of death is Kislev 30, the anniversary in general again depends
 *   on the first anniversary — if that was not Kislev 30, use the day before
 *   Tevet 1.
 * * If the date of death is Adar II, the anniversary is the same day in the
 *   last month of the Hebrew year (Adar or Adar II).
 * * If the date of death is Adar I 30, the anniversary in a Hebrew year that
 *   is not a leap year (in which Adar only has 29 days) is the last day in
 *   Shevat.
 * * In all other cases, use the normal (that is, same month number) anniversary
 *   of the date of death. [Calendrical Calculations p. 113]
 * @example
 * import {getYahrzeit} from '@hebcal/hdate';
 * const dt = new Date(2014, 2, 2); // '2014-03-02' == '30 Adar I 5774'
 * const anniversary = getYahrzeit(5780, dt); // '2/25/2020' == '30 Sh\'vat 5780'
 * @param hyear Hebrew year
 * @param date Gregorian or Hebrew date of death
 * @returns anniversary occurring in `hyear`
 */
export declare function getYahrzeit(hyear: number, date: AnniversaryDate): Date | undefined;
export declare function getYahrzeitHD(hyear: number, date: AnniversaryDate): SimpleHebrewDate | undefined;
/**
 * Calculates a birthday or anniversary (non-yahrzeit).
 * `hyear` must be after original `date` of anniversary.
 * Returns `undefined` when requested year preceeds or is same as original year.
 *
 * Hebcal uses the algorithm defined in "Calendrical Calculations"
 * by Edward M. Reingold and Nachum Dershowitz.
 *
 * The birthday of someone born in Adar of an ordinary year or Adar II of
 * a leap year is also always in the last month of the year, be that Adar
 * or Adar II. The birthday in an ordinary year of someone born during the
 * first 29 days of Adar I in a leap year is on the corresponding day of Adar;
 * in a leap year, the birthday occurs in Adar I, as expected.
 *
 * Someone born on the thirtieth day of Marcheshvan, Kislev, or Adar I
 * has his birthday postponed until the first of the following month in
 * years where that day does not occur. [Calendrical Calculations p. 111]
 * @example
 * import {getBirthdayOrAnniversary} from '@hebcal/hdate';
 * const dt = new Date(2014, 2, 2); // '2014-03-02' == '30 Adar I 5774'
 * const anniversary = getBirthdayOrAnniversary(5780, dt); // '3/26/2020' == '1 Nisan 5780'
 * @param hyear Hebrew year
 * @param date Gregorian or Hebrew date of event
 * @returns anniversary occurring in `hyear`
 */
export declare function getBirthdayOrAnniversary(hyear: number, date: AnniversaryDate): Date | undefined;
export declare function getBirthdayHD(hyear: number, date: AnniversaryDate): SimpleHebrewDate | undefined;