1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license./** * Returns whether the given date or year (in number) is a leap year or not. * based on: https://docs.microsoft.com/en-us/office/troubleshoot/excel/determine-a-leap-year * * @example * ```ts * import { isLeap } from "https://deno.land/std@$STD_VERSION/datetime/is_leap.ts"; * * isLeap(new Date("1970-01-01")); // => returns false * isLeap(new Date("1972-01-01")); // => returns true * isLeap(new Date("2000-01-01")); // => returns true * isLeap(new Date("2100-01-01")); // => returns false * isLeap(1972); // => returns true * ``` * * @param year year in number or Date format */export function isLeap(year: Date | number): boolean {  const yearNumber = year instanceof Date ? year.getFullYear() : year;  return (    (yearNumber % 4 === 0 && yearNumber % 100 !== 0) || yearNumber % 400 === 0  );}