aladaghlou / jalaali-js

JavaScript functions for converting Jalaali and Gregorian calendar systems to each other

Jalaali JavaScript

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

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.

Install

Node.js

Use npm to install:

$ npm install --save jalaali-js

Then import it:

var jalaali = require('jalaali-js')

Browser

Use component to install:

$ component install jalaali/jalaali-js

Then import it:

var jalaali = require('jalaali-js')

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)

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 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 years ahead of the present.

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

License

MIT