Check if a year is a leap year, that's a calendar year that contains an additional day added to keep the calendar year synchronized with the astronomical year or seasonal year.

import { isLeapYear } from "https://deno.land/x/leap_year/mod.ts";

isLeapYear(2014); //=> false
isLeapYear(2016); //=> true
isLeapYear("6 October 2006 00:07:00 GMT"); //=> false
isLeapYear("2000"); //=> false
isLeapYear(new Date(2016, 1, 1)); //=> true
isLeapYear("13 December 400 00:07:00 GMT", true); //=> { year: 400, result: true }

import { isLeapYear } from "@ultirequiem/leap-year";

You can use any CDN 🔥

Eg. ESM ▶ SkyPack / script tag ▶ JSDelivr.

The API is the same on all this platforms.

Autogenerated Documentation 🚀

Was done mainly as usage example.

• Node.js 🦍

npm install -g @ultirequiem/leap-year

• Deno 🦕

deno install https://deno.land/x/leap_year/leap-year.ts

leap-year "13 October 2020 00:07:00 GMT" 400 345
true
true
false

Or with the verbose flag 👇

leap-year "13 October 2020 00:07:00 GMT" 400 345 --verbose # -v
2020 is a leap year.
400 is a leap year.
345 is not a leap year.

• leap_year_utils: Utilities around this package.

• parse_datelike: Parse a number/string/date to a number/string/date.

• leap-year-api: A REST API to know if a year is leap or not.

Open an Issue, I will check it a soon as possible 👀

If you want to hurry me up a bit send me a tweet 😆

Consider supporting me on Patreon if you like my work 🙏

Don't forget to star the repo ⭐

We use Semantic Versioning. For the versions available, see the tags 🏷️

Licensed under the MIT License 📄