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- import toDate from "../toDate/index.js";
- import requiredArgs from "../_lib/requiredArgs/index.js";
- /**
- * @name isLeapYear
- * @category Year Helpers
- * @summary Is the given date in the leap year?
- *
- * @description
- * Is the given date in the leap year?
- *
- * ### v2.0.0 breaking changes:
- *
- * - [Changes that are common for the whole library](https://github.com/date-fns/date-fns/blob/master/docs/upgradeGuide.md#Common-Changes).
- *
- * @param {Date|Number} date - the date to check
- * @returns {Boolean} the date is in the leap year
- * @throws {TypeError} 1 argument required
- *
- * @example
- * // Is 1 September 2012 in the leap year?
- * var result = isLeapYear(new Date(2012, 8, 1))
- * //=> true
- */
- export default function isLeapYear(dirtyDate) {
- requiredArgs(1, arguments);
- var date = toDate(dirtyDate);
- var year = date.getFullYear();
- return year % 400 === 0 || year % 4 === 0 && year % 100 !== 0;
- }
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