nanakshahi

nanakshahi-js

A JavaScript Library to get Nanakshahi Dates and Gurpurabs

Contents

• Usage
  • Polyfill
• API
  • getDateFromNanakshahi(year, month, date)
  • getHolidaysForDay([gregorianDate])
  • getHolidaysForMonth(month, [year])
  • getNanakshahiDate(gregorianDate)
  • findMovableHoliday(holiday, [year])
  • findBikramiFromDate(date, [astro], [isJulian])
  • findDateFromBikramiLunar(year, month, date, [paksh], [leapMonth], [leapDay], [astro])
  • findDateFromBikramiSolar(year, month, date, [astro])
• Acknowledgements
• Contributing

Usage

Install the library via NPM:

npm install nanakshahi

The library can be imported into Node as below:

const n = require('nanakshahi')

const date = new Date()

n.getNanakshahiDate( date )
n.getDateFromNanakshahi( 550, 10, 23 )
n.getHolidaysForDay( date )
n.getHolidaysForMonth( 1 )
n.findMovableHoliday( 'gurunanak' )
n.findBikramiFromDate( date )
n.findDateFromBikramiLunar( 1723, 10, 7 )
n.findDateFromBikramiSolar( 1723, 9, 23 )

Additionally, the package is available for web use via unpkg CDN.

<script src="https://unpkg.com/nanakshahi"></script>

Or via jsDelivr

<script src="https://cdn.jsdelivr.net/npm/nanakshahi/dist/index.min.js"></script>

Want a demo?

Polyfill

While the library does run on most modern browsers, it does not work on IE11.

The library requires Math.sign and Array.prototype.includes. These can be added with the Polyfill below to add IE11 support:

<script crossorigin="anonymous" src="https://polyfill.io/v3/polyfill.min.js?features=Math.sign%2CArray.prototype.includes"></script>

API

getDateFromNanakshahi(year, month, date)

Converts Nanakshahi Date into the Gregorian Calendar

Returns: Object - Gregorian Date

Param	Type	Description
year	number	Nanakshahi Year
month	number	Nanakshahi Month, 1-12
date	number	Nanakshahi Day

Example

getDateFromNanakshahi( 550, 10, 23 )

getHolidaysForDay([gregorianDate])

Returns all Gurpurabs and Holidays for a Date

Returns: Array - Holidays for the day with Date and name in English and Punjabi

Param	Type	Description
[gregorianDate]	Object	JavaScript Date() Object

Example

getHolidaysForDay( new Date() )

getHolidaysForMonth(month, [year])

Returns all Gurpurabs and Holidays for a Nanakshahi Month

Returns: Object - Holidays for the month with Date and name in English and Punjabi

Param	Type	Description
month	number	Nanakshahi Month, 1-12
[year]	number	Nanakshahi Year, default is Current Gregorian Year

Example

getHolidaysForMonth( 1 )

getNanakshahiDate(gregorianDate)

Converts given Gregorian Date to the corresponding date in the Nanakshahi Calendar

Returns: Object - Nanakshahi Date in English and Punjabi

Param	Type	Description
gregorianDate	Object	JavaScript Date() Object

Example

getNanakshahiDate( new Date() )

findMovableHoliday(holiday, [year])

Returns Gregorian Date of Movable Holiday Movable Holidays List:

• gurunanak Parkash Guru Nanak Dev Ji
• bandishhorr Bandi Shhorr Divas / Diwali
• holla Holla Mahalla
• kabeer Birthday Bhagat Kabeer Ji
• ravidaas Birthday Bhagat Ravidaas Ji
• naamdev Birthday Bhagat Naamdev Ji

Returns: Object - Holiday Date with Name in English and Punjabi

Param	Type	Description
holiday	string	Holiday which date will be calculated.
[year]	number	Gregorian year, default is current year.

Example

findMovableHoliday( 'gurunanak' )

findBikramiFromDate(date, [astro], [isJulian])

Returns given date to the corresponding date in the Bikrami Calendar

Returns: Object - Bikrami (Includes Lunar and Solar Date)

Param	Type	Default	Description
date	Object		JavaScript Date() Object
[astro]	boolean	true	Set to false to use Surya Sidhantta instead of Drik Gannit
[isJulian]	boolean	false	Set to true if entered date is in Julian Calendar

Example

findBikramiFromDate( new Date() )

findDateFromBikramiLunar(year, month, date, [paksh], [leapMonth], [leapDay], [astro])

Converts Bikrami Lunar Date into the Gregorian Calendar

Returns: Object - Gregorian Date

Param	Type	Default	Description
year	number		Bikrami Year
month	number		Bikrami Month
date	number		Bikrami Tithi
[paksh]	boolean	false	Lunar Paksh. Default is Sudi, true for Vadi.
[leapMonth]	boolean	false	Set to true if the month is Adhika Month (Mal Maas)
[leapDay]	boolean	false	Set to true if the lunar day spans more than 1 solar day
[astro]	boolean	true	Set to false to use Surya Sidhantta instead of Drik Gannit

Example

findDateFromBikramiLunar( 1723, 10, 7 )

findDateFromBikramiSolar(year, month, date, [astro])

Converts Bikrami Solar Date into the Gregorian Calendar

Returns: Object - Gregorian Date

Param	Type	Default	Description
year	number		Bikrami Year
month	number		Bikrami Month
date	number		Bikrami Day
[astro]	boolean	true	Set to false to use Surya Sidhantta instead of Drik Gannit

Example

findDateFromBikramiSolar( 1723, 9, 23 )

Acknowledgements

I want to thank:

• Guru Sahib, who inspires us into Sikhi.

• Pal Singh Purewal, who explained various concepts in the Bikrami and Nanakshahi Calendars to me and answered my various technical and historical questions. Spent countless hours verifying the calculations done by me.

• E. M. Reingold and N. Dershowitz for their Calendrical Calculations book and Calendrica program code, which serves as the base for the Bikrami calculations done in this library.

• My father, Jasjit Singh, whose curiosity in the Nanakshahi and Bikrami calendar systems inspired me find answers to his technical questions.

Contributing

We're happy to accept suggestions and pull requests!

To get started, clone this repo and run npm install inside this directory.

This repository follows the Airbnb's Javascript Style Guide, with a few minor modifications. Notably, spaces should be included inside parentheses and brackets (weird, right!). An ESLint file is provided, and your code will automatically be checked on-commit for style. It is recommended to install an ESLint plugin for your editor (VS Code's ESLint plugin works out of the box), so you can receive linter suggestions as you type.

When writing commit messages, please follow the seven rules. Markdown and HTML JSDoc documentation is generated automatically, on commit, however if you'd like to preview any changes to documentation, npm run build-docs will update README.md. README.md should not be edited, instead apply modifications to README.hbs.

The general workflow for contributing:

• Fork/create a new branch.
• Write or update existing tests with expected results
• Implement functions/changes
• Add JSDoc function documentation and examples.
• Create a pull request with the changes.