A JavaScript library to get Nanakshahi dates and Gurpurabs
Install the library via NPM:
npm install nanakshahiThe library can be imported into Node as ESM:
import {
findMovableGurpurab,
getDateFromNanakshahi,
getGurpurabsForDate,
getGurpurabsForMonth,
getNanakshahiDate,
} from 'nanakshahi'
const date = new Date()
getNanakshahiDate(date)
getDateFromNanakshahi(550, 10, 23)
getGurpurabsForDate(date)
getGurpurabsForMonth(1)
findMovableGurpurab('gurunanak')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.
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.
getNanakshahiDate(
gregorianDate?):NanakshahiDate
Converts a Gregorian date to the corresponding Nanakshahi date.
Parameters
| Parameter | Type | Description |
|---|---|---|
gregorianDate |
Date |
JavaScript Date object (default: current date). |
Returns
Nanakshahi date in English and Punjabi.
Example
getNanakshahiDate(new Date())getGurpurabsForMonth(
month,year?):GurpurabsForMonth
Returns all Gurpurabs for a Nanakshahi month.
Parameters
| Parameter | Type | Description |
|---|---|---|
month |
number |
Nanakshahi month (1-12). |
year |
number |
Nanakshahi year (default: current Nanakshahi year). |
Returns
Gurpurab list for the month with Gregorian and localized date fields.
Example
getGurpurabsForMonth(1)getGurpurabsForDate(
gregorianDate?):GurpurabName[]
Returns all Gurpurabs that fall on a Gregorian date.
Parameters
| Parameter | Type | Description |
|---|---|---|
gregorianDate |
Date |
JavaScript Date object (default: current date). |
Returns
Gurpurabs for the day with name fields in English and Punjabi.
Example
getGurpurabsForDate(new Date())getDateFromNanakshahi(
year,month,date):NanakshahiDate
Converts a Nanakshahi date into its Gregorian equivalent.
Parameters
| Parameter | Type | Description |
|---|---|---|
year |
number |
Nanakshahi year. |
month |
number |
Nanakshahi month (1-12). |
date |
number |
Nanakshahi day. |
Returns
Gregorian date plus Nanakshahi date in English and Punjabi.
Example
getDateFromNanakshahi(550, 10, 23)findMovableGurpurab(
gurpurab,year?):MovableGurpurab
Returns Gregorian date info for a movable Gurpurab between 2003 CE and 2100 CE.
Supported keys:
gurunanak- Parkash Guru Nanak Dev Jibandichhorr- Bandi Chhorr Divasholla- Holla Mahallakabeer- Birthday Bhagat Kabeer Jiravidaas- Birthday Bhagat Ravidaas Jinaamdev- Birthday Bhagat Naamdev Ji
Parameters
| Parameter | Type | Description |
|---|---|---|
gurpurab |
"ravidaas" | "holla" | "kabeer" | "bandichhorr" | "naamdev" | "gurunanak" |
Movable Gurpurab key. |
year |
number |
Gregorian year (default: current year, range: 2003...2100). |
Returns
Gurpurab date and localized name fields.
Example
findMovableGurpurab('gurunanak')-
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.
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
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