@burglekitt/gmt/dist/plain/validate/isLeapYear.js

Temporal-based date and time utilities with timezone support and polyfill integration

import { Temporal } from "@js-temporal/polyfill";
/**
 * Return true when the given PlainDate falls in a leap year.
 *
 * - A leap year is divisible by 4, except for century years which must be divisible by 400.
 * - Returns false for invalid input strings.
 *
 * @param value ISO PlainDate string
 * @returns boolean indicating whether the date is in a leap year
 *
 * @example isLeapYear("2024-03-15") // true
 * @example isLeapYear("2023-03-15") // false
 * @example isLeapYear("invalid") // false
 */
export function isLeapYear(value) {
    try {
        const date = Temporal.PlainDate.from(value);
        return date.inLeapYear;
    }
    catch {
        return false;
    }
}