startOfISOWeekYear.cjs 1.6 KB

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  1. "use strict";
  2. exports.startOfISOWeekYear = startOfISOWeekYear;
  3. var _index = require("./constructFrom.cjs");
  4. var _index2 = require("./getISOWeekYear.cjs");
  5. var _index3 = require("./startOfISOWeek.cjs");
  6. /**
  7. * The {@link startOfISOWeekYear} function options.
  8. */
  9. /**
  10. * @name startOfISOWeekYear
  11. * @category ISO Week-Numbering Year Helpers
  12. * @summary Return the start of an ISO week-numbering year for the given date.
  13. *
  14. * @description
  15. * Return the start of an ISO week-numbering year,
  16. * which always starts 3 days before the year's first Thursday.
  17. * The result will be in the local timezone.
  18. *
  19. * ISO week-numbering year: http://en.wikipedia.org/wiki/ISO_week_date
  20. *
  21. * @typeParam DateType - The `Date` type, the function operates on. Gets inferred from passed arguments. Allows to use extensions like [`UTCDate`](https://github.com/date-fns/utc).
  22. * @typeParam ResultDate - The result `Date` type, it is the type returned from the context function if it is passed, or inferred from the arguments.
  23. *
  24. * @param date - The original date
  25. * @param options - An object with options
  26. *
  27. * @returns The start of an ISO week-numbering year
  28. *
  29. * @example
  30. * // The start of an ISO week-numbering year for 2 July 2005:
  31. * const result = startOfISOWeekYear(new Date(2005, 6, 2))
  32. * //=> Mon Jan 03 2005 00:00:00
  33. */
  34. function startOfISOWeekYear(date, options) {
  35. const year = (0, _index2.getISOWeekYear)(date, options);
  36. const fourthOfJanuary = (0, _index.constructFrom)(options?.in || date, 0);
  37. fourthOfJanuary.setFullYear(year, 0, 4);
  38. fourthOfJanuary.setHours(0, 0, 0, 0);
  39. return (0, _index3.startOfISOWeek)(fourthOfJanuary);
  40. }