date.addYears()

The addYears method adds or subtracts a specified number of years to the current NepaliDate instance. It recalculates the underlying timestamp while retaining the month and day coordinates, adjusting the day number if the target year has fewer days in that specific month.

ImportCopy Anchor Link

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

SignatureCopy Anchor Link

addYears(years: number): NepaliDate;

ParametersCopy Anchor Link

Return ValueCopy Anchor Link

• Type: NepaliDate
• Returns a new NepaliDate instance with the added or subtracted years. The original instance is not modified.

ExceptionsCopy Anchor Link

Throws an Error if the resulting year falls outside the supported Bikram Sambat calendar range (1976 BS to 2100 BS):

"Resulting date is out of supported range"

ExamplesCopy Anchor Link

Adding and Subtracting YearsCopy Anchor Link

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

const date = new NepaliDate("2081-05-15");

const future = date.addYears(5);
console.log(future.format("YYYY-MM-DD")); // "2086-05-15"

const past = date.addYears(-10);
console.log(past.format("YYYY-MM-DD")); // "2071-05-15"

Day Clamping on Variable Month LengthsCopy Anchor Link

Because month lengths in the Bikram Sambat astronomical calendar vary across years, addYears() automatically clamps the day component if the destination year has fewer days in that month:

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

// 2081 Baisakh 31 (Baisakh 2081 has 31 days)
const date = new NepaliDate(2081, 0, 31);

// If Baisakh in a target year has only 30 days, day clamps to 30
const nextYear = date.addYears(1);
console.log(nextYear.getDate()); // Clamped to valid range

RelatedCopy Anchor Link

• date.addDays(): Add or subtract whole days.
• date.addMonths(): Add or subtract whole months.
• date.diff(): Calculate differences between two dates.