The @timestamp-js/calendar-saka package exports indianNationalCalendar, with sakaCalendar as a convenience alias. It models the official Indian National Calendar using deterministic Gregorian-aligned leap-year rules.

Package

import { gregorianCalendar } from '@timestamp-js/core'
import { indianNationalCalendar } from '@timestamp-js/calendar-saka'

const sakaNewYear = { year: 1946, month: 1, day: 1 }
const gregorian = gregorianCalendar.fromEpochDay(indianNationalCalendar.toEpochDay(sakaNewYear))

gregorian // { year: 2024, month: 3, day: 21 }

Calendar Rules

Chaitra has 31 days when the corresponding Gregorian year is leap, and 30 days otherwise. Months 2-6 have 31 days, and months 7-12 have 30 days.

Week start is a locale concern, not an adapter rule. The example below uses hi-IN-u-ca-indian, reads the locale week start from Intl.Locale#weekInfo when available, and renders left-to-right.

Adapter-Aware Integration

When the adapter is used by calendar, picker, or scheduling UI, pass it through as the active calendar system for views that should behave as native Saka calendars. Date-bearing values should be Saka when the adapter is active, while Gregorian interop metadata can remain available for storage, export, and debugging boundaries.

QCalendar is one adapter-aware consumer. Its adapter guide explains the integration boundary, outside-day behavior, and native month navigation:

Using Timestamp adapters with QCalendar

Calendar Ranges

Use the adapter-aware helpers when you need native Saka weeks or months: