date.isLeapYear()

The isLeapYear method checks whether the active Bikram Sambat year contains 366 or more days based on official solar calendar tables. Because Bikram Sambat year lengths depend on astronomical calculations rather than fixed leap year cycles, this method checks the actual cumulative day count for the year.

ImportCopy Anchor Link

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

SignatureCopy Anchor Link

isLeapYear(): boolean;

ParametersCopy Anchor Link

This method does not take any parameters.

Return ValueCopy Anchor Link

• Type: boolean
• Returns true if the total days in the current Bikram Sambat year is greater than or equal to 366; otherwise returns false.

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Unlike the Gregorian calendar which inserts a leap day every 4 years on February 29, the Bikram Sambat calendar is a sidereal solar calendar where each month's duration is determined by the exact astrological entry (Sankranti) of the Sun into each zodiac constellation. Consequently, the total number of days in a Bikram Sambat year fluctuates between 365 and 366 days based on astronomical observation data.

ExamplesCopy Anchor Link

Checking if a Year is a Leap YearCopy Anchor Link

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

const date2081 = new NepaliDate("2081-01-01");
console.log(date2081.isLeapYear());

const date2080 = new NepaliDate("2080-01-01");
console.log(date2080.isLeapYear());

RelatedCopy Anchor Link

• date.daysInMonth(): Query days in a specific month.
• date.getYear(): Retrieve current year.