NepaliDate Library

Overview

The NepaliDate library provides a way to work with Nepali (Bikram Sambat) dates in TypeScript/JavaScript. It allows you to create, manipulate, format, and convert between Nepali and Gregorian dates.

Installation

npm install nepali-date-library

Importing the Library

import { NepaliDate } from 'nepali-date-library';

Class: `NepaliDate`

Constructors

new NepaliDate();
new NepaliDate(date: Date | NepaliDate | number | string);
new NepaliDate(year: number, month: number, day: number);

Creates a NepaliDate instance.
Accepts either no arguments (current date), a JavaScript Date, another NepaliDate, a timestamp, or a formatted date string.
Can also accept year, month (0-11), and day (1-32) as separate arguments.

Methods

Date Conversion

//PreBuild Functions

import { ADtoBS, BStoAD } from 'nepali-date-library';
// Convert AD to BS
const bsDate = ADtoBS('2025-02-22');  // Returns: '2081-10-10'
// Convert BS to AD
const adDate = BStoAD('2081-10-14');  // Returns: '2025-02-26'

//Class Functions
const adDate = new NepaliDate().getEnglishDate();

Getters

getYear(): number;
getMonth(): number;
getDate(): number;
getDay(): number;
getHours(): number;
getMinutes(): number;
getSeconds(): number;
getMilliseconds(): number;
getTime(): number;

Returns individual date components like year, month (0-11), day (1-32), and other time properties.

Setters

setYear(year: number): void;
setMonth(month: number): void;
setDate(day: number): void;
set(year: number, month: number, day: number): void;

Updates the Nepali date components and synchronizes the internal timestamp.

Formatting

format(formatStr: string): string;

Formats the date based on the provided format string.
Available Formats:
- English
  - YYYY - Full Year (e.g., 2080)
  - MM - Month with leading zero (01-12)
  - M - Month without leading zero (1-12)
  - MMM - Short month name (Bai, Cha)
  - MMMM - Long month name (Baisakh, Chaitra)
  - DD - Day with leading zero (01-32)
  - D - Day without leading zero (1-32)
  - DDD - Short day name (Sun, Sat)
  - DDDD - Full day name (Sunday)
- Nepali
  - yyyy - Full Year (e.g., २०८१)
  - mm - Month with leading zero (०१-१२)
  - m - Month without leading zero (१-१२)
  - mmm - Short month name (बै, चै)
  - mmmm - Long month name (बैशाख, चैत्र)
  - dd - Day with leading zero (०१-३२)
  - d - Day without leading zero (१-३२)
  - ddd - Short day name (आइत, शनि)
  - dddd - Full day name (आइतबार)

Date Manipulation

addDays(days: number): NepaliDate;
addMonths(months: number): NepaliDate;
addYears(years: number): NepaliDate;

Adds a specified number of days, months, or years to the date and returns a new NepaliDate instance.

Additional Methods

`daysInMonth(): number`

Returns the number of days in the current month.

const date = new NepaliDate(2080, 5, 1);
console.log(date.daysInMonth()); // Outputs the number of days in the given month

`isLeapYear(): boolean`

Checks if the current year is a leap year in the Nepali calendar.

const date = new NepaliDate(2080, 1, 1);
console.log(date.isLeapYear()); // Returns true if it is a leap year

`getWeeksInMonth(): number`

Calculates the number of weeks in the current month.

const date = new NepaliDate(2080, 5, 1);
console.log(date.getWeeksInMonth()); // Outputs the number of weeks

`diff(date: NepaliDate, unit: 'year' | 'month' | 'day'): number`

Calculates the difference between two NepaliDate instances in the specified unit (year, month, or day).

const date1 = new NepaliDate(2080, 5, 10); // Example date
const date2 = new NepaliDate(2079, 5, 10); // Another example date

console.log(date1.diff(date2, 'day'));   // Outputs the difference in days
console.log(date1.diff(date2, 'month')); // Outputs the difference in months
console.log(date1.diff(date2, 'year'));  // Outputs the difference in years

`startOfDay(): NepaliDate`

Returns a new NepaliDate representing the start of the current day (00:00:00).

const date = new NepaliDate(2080, 5, 10);
console.log(date.startOfDay());

`endOfDay(): NepaliDate`

Returns a new NepaliDate representing the end of the current day (23:59:59.999).

const date = new NepaliDate(2080, 5, 10);
console.log(date.endOfDay());

`startOfMonth(): NepaliDate`

Returns a new NepaliDate representing the first day of the current month.

const date = new NepaliDate(2080, 5, 10);
console.log(date.startOfMonth());

`endOfMonth(): NepaliDate`

Returns a new NepaliDate representing the last day of the current month.

const date = new NepaliDate(2080, 5, 10);
console.log(date.endOfMonth());

`startOfYear(): NepaliDate`

Returns a new NepaliDate representing the first day of the current Nepali year (1st Baisakh).

const date = new NepaliDate(2080, 5, 10);
console.log(date.startOfYear());

`endOfYear(): NepaliDate`

Returns a new NepaliDate representing the last day of the current Nepali year (last day of Chaitra).

const date = new NepaliDate(2080, 5, 10);
console.log(date.endOfYear());

Function Overview

`getMonthName(month: number, short: boolean, nepali: boolean): string`

Returns

Returns the name of the specified Nepali month in Nepali or English.

NepaliDate.getMonthName(2, false, false); // "Asar"

`getDayName(day: number, short: boolean, nepali: boolean): string`

Returns

Returns the name of the specified day of the week in Nepali or English.

NepaliDate.getDayName(0, false, true); // "आइतबार"

`isValid(year: number, month: number, day: number): boolean`

Returns

Checks if the specified Nepali date is valid.

NepaliDate.isValid(2080, 4, 20); // true

`getCalendarDays(year: number, month: number): Object`

Returns

Generates calendar days for a given month, including trailing/leading days from adjacent months. It returns an object containing the calendar days for the previous month, the current month, and the next month. Each month includes day objects with the date and a flag indicating whether the day belongs to the current month.

return { prevRemainingDays: number, prevMonth: { year: number, month: number, days: number[] }, currentMonth: { year: number, month: number, days: number[] }, nextMonth: { year: number, month: number, days: number[] }, remainingDays: number }

Parameters

year: Nepali year (e.g., 2081)
month: Nepali month (0-11), where 0 represents the first month.

Example

NepaliDate.getCalendarDays(2081, 4);

`clone(): NepaliDate`

Returns

Creates a copy of the current NepaliDate instance.

const date = new NepaliDate(2080, 4, 20);
const clonedDate = date.clone();

`isAfter(date: NepaliDate): boolean`

Returns

Checks if this date comes after the specified date.

const date = new NepaliDate(2080, 4, 20);
date.isAfter(new NepaliDate(2080, 3, 15)); // true

`isBefore(date: NepaliDate): boolean`

Returns

Checks if this date comes before the specified date.

const date = new NepaliDate(2080, 4, 20);
date.isBefore(new NepaliDate(2080, 5, 10)); // true

`isEqual(date: NepaliDate): boolean`

Returns

Checks if this date is equal to the specified date.

const date = new NepaliDate(2080, 4, 20);
date.isEqual(new NepaliDate(2080, 4, 20)); // true

`isSame(date: NepaliDate, unit: 'year' | 'month' | 'day'): boolean`

Returns

Checks if this date is the same as the specified date for the given unit.

const date = new NepaliDate(2080, 4, 20);
date.isSame(new NepaliDate(2080, 4, 15), 'month'); // true

Example Usage

const today = new NepaliDate();
console.log(today);

const formatted = today.format('YYYY-MM-DD');
console.log(formatted);

const futureDate = today.addDays(10);
console.log(futureDate);

const pastDate = today.addDays(-10);
console.log(pastDate);

Acknowledgements

This project was inspired by nepali-date.

Error Handling

Throws an error if an invalid date format is used.
Throws an error if the Nepali date is out of range.

License

MIT License