temporal-hijri

Temporal Calendar Protocol implementation for the Hijri calendar. Works with the TC39 Temporal proposal (Stage 3) and @js-temporal/polyfill.

Provides UaqCalendar (Umm al-Qura) and FcnaCalendar (FCNA/ISNA) as plug-in calendars for Temporal.PlainDate. The underlying conversion logic comes from hijri-core.

Installation

pnpm add temporal-hijri hijri-core
# Add the polyfill if native Temporal is unavailable:
pnpm add @js-temporal/polyfill

Quick Start

import { Temporal } from '@js-temporal/polyfill';
import { uaqCalendar } from 'temporal-hijri';

const isoDate = Temporal.PlainDate.from('2023-03-23');

console.log(uaqCalendar.year(isoDate));      // 1444
console.log(uaqCalendar.month(isoDate));     // 9  (Ramadan)
console.log(uaqCalendar.day(isoDate));       // 1

// Convert Hijri coordinates to ISO
const ramadan = uaqCalendar.dateFromFields({ year: 1444, month: 9, day: 1 });
console.log(ramadan.toString()); // "2023-03-23"

// Date arithmetic in Hijri space
const { Duration } = Temporal;
const nextMonth = uaqCalendar.dateAdd(isoDate, new Duration(0, 1));
console.log(uaqCalendar.month(nextMonth)); // 10 (Shawwal)

Calendars

Calendar	ID	Authority	Method	Coverage
Umm al-Qura	hijri-uaq	KACST, Saudi Arabia	Pre-calculated tables	1318-1500 AH
FCNA/ISNA	hijri-fcna	Fiqh Council of NA	Astronomical new moon	Unbounded

Documentation

Full reference in the wiki.

• API Reference
• Architecture
• Examples

Conversion behavior

Conversions between ISO and Hijri dates are pure calendar-date mappings: the same ISO date always maps to the same Hijri date on every machine, regardless of the host's timezone. Temporal.PlainDate carries no time-of-day information, and the underlying hijri-core engine operates on UTC calendar days, so there is no timezone dependency.

Note: the Islamic calendar begins a new day at sunset, not midnight. This library follows the civil-calendar convention (midnight boundary) used by most software. Sunset day-start determination is out of scope.

Related

• hijri-core: the underlying calendar engine
• luxon-hijri: Hijri support for Luxon
• pray-calc: Islamic prayer times

License

MIT. Copyright (c) 2026 Aric Camarata. See LICENSE.