setMonth.js 1.5 KB

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  1. import { constructFrom } from "./constructFrom.js";
  2. import { getDaysInMonth } from "./getDaysInMonth.js";
  3. import { toDate } from "./toDate.js";
  4. /**
  5. * The {@link setMonth} function options.
  6. */
  7. /**
  8. * @name setMonth
  9. * @category Month Helpers
  10. * @summary Set the month to the given date.
  11. *
  12. * @description
  13. * Set the month to 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 date to be changed
  19. * @param month - The month index to set (0-11)
  20. * @param options - The options
  21. *
  22. * @returns The new date with the month set
  23. *
  24. * @example
  25. * // Set February to 1 September 2014:
  26. * const result = setMonth(new Date(2014, 8, 1), 1)
  27. * //=> Sat Feb 01 2014 00:00:00
  28. */
  29. export function setMonth(date, month, options) {
  30. const _date = toDate(date, options?.in);
  31. const year = _date.getFullYear();
  32. const day = _date.getDate();
  33. const midMonth = constructFrom(options?.in || date, 0);
  34. midMonth.setFullYear(year, month, 15);
  35. midMonth.setHours(0, 0, 0, 0);
  36. const daysInMonth = getDaysInMonth(midMonth);
  37. // Set the earlier date, allows to wrap Jan 31 to Feb 28
  38. _date.setMonth(month, Math.min(day, daysInMonth));
  39. return _date;
  40. }
  41. // Fallback for modularized imports:
  42. export default setMonth;