Getting Started

Installation

Install the library using your preferred package manager:

npm

npm install nepali-date-library

yarn

yarn add nepali-date-library

pnpm

pnpm add nepali-date-library

Importing

ES Modules (Recommended)

import { NepaliDate, ADtoBS, BStoAD } from "nepali-date-library";

CommonJS

const { NepaliDate, ADtoBS, BStoAD } = require("nepali-date-library");

Import Specific Utilities

You can also import specific constants if needed:

import {
  NepaliDate,
  ADtoBS,
  BStoAD,
  // Constants
  MONTH_EN,
  MONTH_NP,
  MONTH_SHORT_EN,
  MONTH_SHORT_NP,
  WEEK_EN,
  WEEK_NP,
  WEEK_SHORT_EN,
  WEEK_SHORT_NP,
  NUMBER_NP,
  NEPALI_DATE_MAP,
} from "nepali-date-library";

Quick Start

Creating a NepaliDate

There are multiple ways to create a NepaliDate instance:

// Current date and time
const today = new NepaliDate();

// From JavaScript Date object
const fromDate = new NepaliDate(new Date());

// From year, month (0-indexed), day
const specific = new NepaliDate(2082, 9, 15); // Magh 15, 2082

// From date string (YYYY-MM-DD format)
const fromString = new NepaliDate("2082-10-01");

// From timestamp
const fromTimestamp = new NepaliDate(Date.now());

// Clone another NepaliDate
const clone = new NepaliDate(today);

Month is 0-indexed

When creating a date with year, month, and day, the month is 0-indexed (0 = Baisakh, 11 = Chaitra), similar to JavaScript's Date object.

Date Conversion

import { ADtoBS, BStoAD } from "nepali-date-library";

// Convert AD (Gregorian) to BS (Nepali)
const bsDate = ADtoBS("2026-01-14");
console.log(bsDate); // '2082-10-01'

// Convert BS (Nepali) to AD (Gregorian)
const adDate = BStoAD("2082-10-01");
console.log(adDate); // '2026-01-14'

// Using NepaliDate class
const nepaliDate = new NepaliDate();
const englishDate = nepaliDate.getEnglishDate(); // Returns JavaScript Date object

Formatting Dates

const date = new NepaliDate(2082, 9, 15);

// English format tokens (uppercase)
console.log(date.format("YYYY-MM-DD")); // 2082-10-15
console.log(date.format("MMMM DD, YYYY")); // Magh 15, 2082
console.log(date.format("MMM D, YYYY")); // Mag 15, 2082
console.log(date.format("DDDD")); // Wednesday

// Nepali format tokens (lowercase)
console.log(date.format("yyyy-mm-dd")); // २०८२-१०-१५
console.log(date.format("mmmm dd, yyyy")); // माघ १५, २०८२
console.log(date.format("dddd")); // बुधबार

Date Manipulation

const date = new NepaliDate(2082, 9, 15);

// Add days, months, or years (returns new instance)
const tomorrow = date.addDays(1);
const nextMonth = date.addMonths(1);
const nextYear = date.addYears(1);

// Go backwards with negative values
const yesterday = date.addDays(-1);
const lastMonth = date.addMonths(-1);

Date Comparison

const date1 = new NepaliDate(2082, 5, 10);
const date2 = new NepaliDate(2082, 5, 20);

// Comparison methods
console.log(date1.isBefore(date2)); // true
console.log(date1.isAfter(date2)); // false
console.log(date1.isEqual(date2)); // false

// Check if same year/month/day
console.log(date1.isSame(date2, "year")); // true
console.log(date1.isSame(date2, "month")); // true
console.log(date1.isSame(date2, "day")); // false

// Calculate difference
console.log(date1.diff(date2, "day")); // -10
console.log(date1.diff(date2, "month")); // 0

TypeScript Support

The library is written in TypeScript and includes full type definitions. You get complete IntelliSense support in VS Code and other TypeScript-aware editors.

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

const date: NepaliDate = new NepaliDate();

// All methods are fully typed
const year: number = date.getYear();
const formatted: string = date.format("YYYY-MM-DD");
const isValid: boolean = date.isValid();

Quick Reference

Most Used Methods

Method	Description	Example
getYear()	Get Nepali year	date.getYear() → 2082
getMonth()	Get Nepali month (0-11)	date.getMonth() → 9
getDate()	Get Nepali day	date.getDate() → 15
format(str)	Format date as string	date.format('YYYY-MM-DD')
addDays(n)	Add n days	date.addDays(7)
addMonths(n)	Add n months	date.addMonths(1)
addYears(n)	Add n years	date.addYears(1)
isBefore(date)	Check if before another date	date1.isBefore(date2)
isAfter(date)	Check if after another date	date1.isAfter(date2)
clone()	Create a copy	date.clone()

Conversion Functions

Function	Description	Example
ADtoBS(str)	Convert AD to BS	ADtoBS('2026-01-14') → '2082-10-01'
BStoAD(str)	Convert BS to AD	BStoAD('2082-10-01') → '2026-01-14'