Hebcal is a perpetual Jewish Calendar. This library converts between Hebrew and Gregorian dates, and generates lists of Jewish holidays for any year (past, present or future). Shabbat and holiday candle lighting and havdalah times are approximated based on location. Torah readings (Parashat HaShavua), Daf Yomi, and counting of the Omer can also be specified. Hebcal also includes algorithms to calculate yahrzeits, birthdays and anniversaries.

Hebcal was created in 1994 by Danny Sadinoff as a Unix/Linux program written in C, inspired by similar functionality written in Emacs Lisp. The initial JavaScript port was released in 2014 by Eyal Schachter (age 15). This ECMAScript 2015 implementation was released in 2020 by Michael J. Radwin. @hebcal/core targets both browser-based JavaScript and server-side Node.js.

Many users of this library will utilize the HebrewCalendar and HDate interfaces.

$ npm install @hebcal/core

import {HebrewCalendar, HDate, Location, Event} from '@hebcal/core';

const options: CalOptions = {
  year: 1981,
  isHebrewYear: false,
  candlelighting: true,
  location: Location.lookup('San Francisco'),
  sedrot: true,
  omer: true,
};
const events = HebrewCalendar.calendar(options);

for (const ev of events) {
  const hd = ev.getDate();
  const date = hd.greg();
  console.log(date.toLocaleDateString(), ev.render('en'), hd.toString());
}