nepali-date

A Nepali Date library for nepali date parsing and formatting.

The lunar calendar based on Bikram Samvat seems to have varied from it's original specification. As the number of days on each month do not adhere to their standards when checked over a period.

1 Baishakh	30.950 exactly
2 Jestha	31.429 exactly
3 Ashadh	31.638 exactly
4 Shrawan	31.463 exactly
5 Bhadra	31.012 exactly
6 Ashwin	30.428 exactly
7 Kartik	29.879 exactly
8 Mangsir	29.475 exactly
9 Poush		29.310 exactly
10 Magh		29.457 exactly
11 Falgun	29.841 exactly
12 Chaitra	30.377 exactly
+++++++++++++++++++++++++++++++
Total		365.259

The exact length of each month is the time taken by the Sun to move through a full zodiac sign.

Since, the nepali calendar didn't follow this closely. We have to use a map based implementation. So, the library would work only within a certain period of time. At the moment it works between 2000 BS to 2100 BS.

Installation

$ yarn add nepali-date

or

$ npm install nepali-date

Usage

const NepaliDate = require('nepali-date');

const d1 = new NepaliDate('2075-03-05');
const d2 = new NepaliDate('2075/3/5');
const d3 = new NepaliDate('2075.03.5');
const dp1 = new NepaliDate('2075/03'); // 2075/03/01
const dp2 = new NepaliDate('2075'); // 2075/01/01

// Create one from English Date
const d4 = new NepaliDate(new Date('2017-01-15')); 

// Create using year, month, date
const d5 = new NepaliDate(2075, 0, 1); 
    // Note that the month starts with 0 (for Baisakh)
    // To make it work similar with javascript Date object
  
// You could also use values higher or lower (negative) to wrap around
const d6 = new NepaliDate(2075, 13, 1); // '2076/2/1'
const d7 = new NepaliDate(2075, -1, 1); // '2074/12/1'

// Format date in nepali 
d6.format('yyyy-mm-dd'); // २०७५-०२-०१
d6.format('YYY-MM-DD'); // 075-02-01
d6.format('mmmm d, yyyy ddd'); // जेष्ठ १, २०७५ मंगल
d6.format('MMM D, YYYY DDD'); // Jes 1, 2075 Tue

// Retrieve english date from NepaliDate
d1.getEnglishDate(); // Return Date object
d1.getTime();        // Return timestamp in milliseconds

Bonus

Install the package globally and get access to command lines ad2bs and bs2ad to convert dates from one format to another from command line.

npm install -g nepali-date

or

yarn global add nepali-date

This will install the nepali-date library globally, installing ad2bs and bs2ad as command lines.

ad2bs 2018-01-01
bs2ad 2075-01-01

API

Constructors

• new NepaliDate()
  Create a nepali date for current time.

• new NepaliDate(string)
  Create a date parsing string in the following format yyyy[./-]mm[./-].dd.
  

  new NepaliDate('2075-03-05')
new NepaliDate('2075/3/23')
new NepaliDate('2075.1.24')
new NepaliDate('2075.1') // Day is 1 by default
new NepaliDate('2075') // Month and Day is 1 by default
  

  If string is not a valid date, an error is thrown

• new NepaliDate(year, monthIndex, day)
  Create nepali date for the given year, month and day. Note that the month value is an index starting at 0, i.e., 0 for Baisakh, 1 for Jestha and so on. The values do not need to be bound to the valid values, but would correctly round off for any value for monthIndex or day. For example, monthIndex 12 would mean month 0 for year + 1. Similarly, the day values will also perform the similar transformation, for example. day 40 would mean day 8, 9, 10, or 11 of next month depending on the number of days in the given month.

  new NepaliDate(2075, 0, 1); // 2075/01/01
  

• new NepaliDate(timestamp)
  Create nepali date from a unix timestamp (number of milliseconds since epoch similar to the one used by Date).

  new NepaliDate(Date.now()) // Create current date

• new NepaliDate(Date)
  Create nepali date from javascript Date.

  new NepaliDate(new Date('2017/01/23')) // 2073/10/10
  

• new NepaliDate(NepaliDate)
  Create a clone of another NepaliDate.

getYear()

Retrieve full nepali year (2074, 2075, etc)

getMonth()

Retrieve month index (0 for Baisakh, 1 for Jestha) so on.

getDate()

Retrieve day of month (1, 2, ...)

getHours(), getMinutes(), getSeconds(), getMilliseconds()

Hours, minutes, seconds and milliseconds similar to javascript Date.

getEnglishDate()

Retrieve Date object corresponding to the Nepali date

set(year, month, date)

Change date to given year, month and day of month

setYear(year)

Change the year of the existing date, without changing other parameters (month, date)

setMonth(monthIndex)

Change the month of the existing date, without chaning other parameters (year, date). Note that the values can extend beyong 0-11, which leads to change in year values as well. Ex, setting month to 12 will set month to Baisakh of next year, similarly setting month to -1 will set month to Chaitra of previous year.

setDate(day)

Change the day of month of the existing date, without changing other parameters (year, month). Note that the values can extend beyond the normal days in month. Ex, setting day to 0, will change the date to the last date of previous month, setting date to 35 will change the date to some day in the next month (3, 4, 5, depending on how many days are there in the month)

format(formatStr)

Format the date to provide various output based on format string

YYYY - 4 digit of year (2075)
yyyy - 4 digit of year in nepali unicode (२०७५)
YYY  - 3 digit of year (075)
yyy  - 3 digit of year (०७५)
YY   - 2 digit of year
yy   - 2 digit of year in nepali unicode (७५)
M    - month number (1 - 12)
m    - month number (१ - १२) in nepali unicode
MM   - month number with 0 padding (01 - 12)
mm   - month number in nepali unicode with 0 padding - (०१-१२)
MMM  - short month name (Bai, Jes, Asa, Shr, etc.)
mmm  - short month name in nepali unicde (ब‍ै, जे, अ, श्रा, etc)
MMMM - full month name (Baisakh, Jestha, Asar, ...)
mmmm - full month name nepali (बैसाख, जेष्ठ, ...)
D    - Day of Month (1, 2, ... 31, 32)
d    - Day of Month in Nepali unicode (१, २, ३ ... ३१, ३२)
DD   - Day of Month with zero padding (01, 02, ...)
dd   - Day of Month with zero padding in Nepali unicode (०१, ०२, ...)
DDD  - Day of Week short form (Sun, Mon, Tue, ...)
ddd  - Day of week in short form nepali (आइत, सोम, ...)
DDDD - Day of week full form (Sunday, Monday, Tuesday, ...)
dddd - Day of week full form nepali (आइतबार, सोमबार, ...)

Any other character is printed as is. If you need to print the special characters (YMDymd), enclose them within quotes.