index.js 716 B

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  1. import toDate from "../toDate/index.js";
  2. import requiredArgs from "../_lib/requiredArgs/index.js";
  3. /**
  4. * @name getDecade
  5. * @category Decade Helpers
  6. * @summary Get the decade of the given date.
  7. *
  8. * @description
  9. * Get the decade of the given date.
  10. *
  11. * @param {Date|Number} date - the given date
  12. * @returns {Number} the year of decade
  13. * @throws {TypeError} 1 argument required
  14. *
  15. * @example
  16. * // Which decade belongs 27 November 1942?
  17. * const result = getDecade(new Date(1942, 10, 27))
  18. * //=> 1940
  19. */
  20. export default function getDecade(dirtyDate) {
  21. requiredArgs(1, arguments);
  22. var date = toDate(dirtyDate);
  23. var year = date.getFullYear();
  24. var decade = Math.floor(year / 10) * 10;
  25. return decade;
  26. }