nanakshahi

nanakshahi-js

A JavaScript library to get Nanakshahi dates and Gurpurabs

Contents

• Usage
  • NPM
  • CDN
• Notes
  • Nanakshahi Calendar
  • JavaScript Date() Object
• API
  • getDateFromNanakshahi(year, month, date)
  • getGurpurabsForDay([gregorianDate])
  • getGurpurabsForMonth(month, [year])
  • getNanakshahiDate([gregorianDate])
  • findMovableGurpurab(gurpurab, [year])
• Acknowledgements
• Contributing
• License

Usage

NPM

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.getGurpurabsForDay( date )
n.getGurpurabsForMonth( 1 )
n.findMovableGurpurab( 'gurunanak' )

Want a demo?

CDN

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>

Notes

Nanakshahi Calendar

This library is based on the Nanakshahi calendar passed by Sri Akal Takht Sahib in 2003 CE.

All Gurpurabs and historical dates are reckoned with their solar dates. An exception to this are the movable lunar dates which are to be reckoned using the Bikrami calendar until further Panthic consensus.

The Nanakshahi functions will only calculate dates after Nanakshahi adoption in 2003 CE. Any dates before March 14, 2003 CE (535 NS) will return with an Out of Range error.

JavaScript Date() Object

In this library, the Date object has been given in the local time of the client. This ensures that the Gregorian date calculated by the functions is correct regardless of timezone.

API

getDateFromNanakshahi(year, month, date)

Converts Nanakshahi Date into the Gregorian Calendar

Returns: Object - Gregorian Date + Nanakshahi Date in English and Punjabi

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

Example

getDateFromNanakshahi( 550, 10, 23 )

getGurpurabsForDay([gregorianDate])

Returns all Gurpurabs for a Date

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

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

Example

getGurpurabsForDay( new Date() )

getGurpurabsForMonth(month, [year])

Returns all Gurpurabs for a Nanakshahi Month

Returns: Object - Gurpurabs 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 Nanakshahi Year.

Example

getGurpurabsForMonth( 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	Default	Description
[gregorianDate]	Object	new Date()	JavaScript Date() Object

Example

getNanakshahiDate( new Date() )

findMovableGurpurab(gurpurab, [year])

Returns Gregorian Date of Movable Gurpurab

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

Param	Type	Description
gurpurab	string	Movable Gurpurabs: gurunanak - Parkash Guru Nanak Dev Ji bandichhorr - Bandi Chhorr Divas / Diwali holla - Holla Mahalla kabeer - Birthday Bhagat Kabeer Ji ravidaas - Birthday Bhagat Ravidaas Ji naamdev - Birthday Bhagat Naamdev Ji
[year]	number	Gregorian year, default is current year.

Example

findMovableGurpurab( 'gurunanak' )

Acknowledgements

• 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 their calendar functions, which serve as the base for the movable Gurpurab calculations done in this library.

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

Contributing

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 Conventional Commits specification.

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

License

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, as per version 3 of the License.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this program. If not, see https://www.gnu.org/licenses/.