Jalaali Calendar Utilities for Deno

A few utility functions for converting Jalaali (Jalali, Persian, Khayyami, Khorshidi, Shamsi) and Gregorian calendar systems to each other.

This repo is a Typescript implementation of https://github.com/jalaali/jalaali-js and is suited to be used with Deno.

Usage

import * as jalaali from 'https://deno.land/x/jalaali@0.0.1/mod.ts';

API

toJalaali(gy, gm, gd)

Converts a Gregorian date to Jalaali.

jalaali.toJalaali(2016, 4, 11) // { jy: 1395, jm: 1, jd: 23 }

toJalaali(date)

Converts a JavaScript Date object to Jalaali.

jalaali.toJalaali(new Date(2016, 3, 11)) // { jy: 1395, jm: 1, jd: 23 }

toGregorian(jy, jm, jd)

Converts a Jalaali date to Gregorian.

jalaali.toGregorian(1395, 1, 23) // { gy: 2016, gm: 4, gd: 11 }

isValidJalaaliDate(jy, jm, jd)

Checks whether a Jalaali date is valid or not.

jalaali.isValidJalaaliDate(1394, 12, 30) // false
jalaali.isValidJalaaliDate(1395, 12, 30) // true

isLeapJalaaliYear(jy)

Is this a leap year or not?

jalaali.isLeapJalaaliYear(1394) // false
jalaali.isLeapJalaaliYear(1395) // true

jalaaliMonthLength(jy, jm)

The number of days in a given month in a Jalaali year.

jalaali.jalaaliMonthLength(1394, 12) // 29
jalaali.jalaaliMonthLength(1395, 12) // 30

jalCal(jy)

This function determines if the Jalaali (Persian) year is a leap (366-day long) or is the common year (365 days), and finds the day in March (Gregorian calendar) of the first day of the Jalaali year (jy).

jalaali.jalCal(1390) // { leap: 3, gy: 2011, march: 21 }
jalaali.jalCal(1391) // { leap: 0, gy: 2012, march: 20 }
jalaali.jalCal(1392) // { leap: 1, gy: 2013, march: 21 }
jalaali.jalCal(1393) // { leap: 2, gy: 2014, march: 21 }
jalaali.jalCal(1394) // { leap: 3, gy: 2015, march: 21 }
jalaali.jalCal(1395) // { leap: 0, gy: 2016, march: 20 }

j2d(jy, jm, jd)

Converts a date of the Jalaali calendar to the Julian Day number.

jalaali.j2d(1395, 1, 23) // 2457490

d2j(jdn)

Converts the Julian Day number to a date in the Jalaali calendar.

jalaali.d2j(2457490) // { jy: 1395, jm: 1, jd: 23 }

g2d(gy, gm, gd)

Calculates the Julian Day number from Gregorian or Julian calendar dates. This integer number corresponds to the noon of the date (i.e. 12 hours of Universal Time). The procedure was tested to be good since 1 March, -100100 (of both calendars) up to a few million years into the future.

jalaali.g2d(2016, 4, 11) // 2457490

d2g(jdn)

Calculates Gregorian and Julian calendar dates from the Julian Day number (jdn) for the period since jdn=-34839655 (i.e. the year -100100 of both calendars) to some millions of years ahead of the present.

jalaali.d2g(2457490) // { gy: 2016, gm: 4, gd: 11 }

jalaaliToDateObject(jy, jm, jd)

Convert Jalaali calendar date to javascript Date object by giving Jalaali year, month, and day.

jalaali.jalaaliToDateObject(1400, 4, 30) // new Date(2021, 6, 21)

jalaaliWeek(jy, jm, jd)

Returns Saturday and Friday day of the current week (week starts on Saturday)

jalaali.jalaaliWeek(1400, 4, 30) // { saturday: { jy: 1400, jm: 4, jd: 26 }, friday: { jy: 1400, jm: 5, jd: 1 } }

Run Tests

deno --unstable test

About

Jalali calendar is a solar calendar that was used in Persia, variants of which today are still in use in Iran as well as Afghanistan. Read more on Wikipedia or see Calendar Converter.

Calendar conversion is based on the algorithm provided by Kazimierz M. Borkowski and has a very good performance.

License

MIT