sharingapples / nepali-date

A Nepali date library for extracting dates based on Bikram Sambat (B. S.) and perform conversions with Gregorian calendar (A. D.)
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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

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.