startOfDecade.cjs 1.4 KB

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  1. "use strict";
  2. exports.startOfDecade = startOfDecade;
  3. var _index = require("./toDate.cjs");
  4. /**
  5. * The {@link startOfDecade} options.
  6. */
  7. /**
  8. * @name startOfDecade
  9. * @category Decade Helpers
  10. * @summary Return the start of a decade for the given date.
  11. *
  12. * @description
  13. * Return the start of a decade for the given date.
  14. *
  15. * @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).
  16. * @typeParam ResultDate - The result `Date` type, it is the type returned from the context function if it is passed, or inferred from the arguments.
  17. *
  18. * @param date - The original date
  19. * @param options - An object with options
  20. *
  21. * @returns The start of a decade
  22. *
  23. * @example
  24. * // The start of a decade for 21 October 2015 00:00:00:
  25. * const result = startOfDecade(new Date(2015, 9, 21, 00, 00, 00))
  26. * //=> Jan 01 2010 00:00:00
  27. */
  28. function startOfDecade(date, options) {
  29. // TODO: Switch to more technical definition in of decades that start with 1
  30. // end with 0. I.e. 2001-2010 instead of current 2000-2009. It's a breaking
  31. // change, so it can only be done in 4.0.
  32. const _date = (0, _index.toDate)(date, options?.in);
  33. const year = _date.getFullYear();
  34. const decade = Math.floor(year / 10) * 10;
  35. _date.setFullYear(decade, 0, 1);
  36. _date.setHours(0, 0, 0, 0);
  37. return _date;
  38. }