index.js 737 B

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  1. import toDate from "../toDate/index.js";
  2. import requiredArgs from "../_lib/requiredArgs/index.js";
  3. /**
  4. * @name isLeapYear
  5. * @category Year Helpers
  6. * @summary Is the given date in the leap year?
  7. *
  8. * @description
  9. * Is the given date in the leap year?
  10. *
  11. * @param {Date|Number} date - the date to check
  12. * @returns {Boolean} the date is in the leap year
  13. * @throws {TypeError} 1 argument required
  14. *
  15. * @example
  16. * // Is 1 September 2012 in the leap year?
  17. * const result = isLeapYear(new Date(2012, 8, 1))
  18. * //=> true
  19. */
  20. export default function isLeapYear(dirtyDate) {
  21. requiredArgs(1, arguments);
  22. var date = toDate(dirtyDate);
  23. var year = date.getFullYear();
  24. return year % 400 === 0 || year % 4 === 0 && year % 100 !== 0;
  25. }