date-fns/setWeekYear.d.ts

import type {
  FirstWeekContainsDateOptions,
  LocalizedOptions,
  WeekOptions,
} from "./types.js";
/**
 * The {@link setWeekYear} function options.
 */
export interface SetWeekYearOptions
  extends LocalizedOptions<"options">,
    WeekOptions,
    FirstWeekContainsDateOptions {}
/**
 * @name setWeekYear
 * @category Week-Numbering Year Helpers
 * @summary Set the local week-numbering year to the given date.
 *
 * @description
 * Set the local week-numbering year to the given date,
 * saving the week number and the weekday number.
 * The exact calculation depends on the values of
 * `options.weekStartsOn` (which is the index of the first day of the week)
 * and `options.firstWeekContainsDate` (which is the day of January, which is always in
 * the first week of the week-numbering year)
 *
 * Week numbering: https://en.wikipedia.org/wiki/Week#The_ISO_week_date_system
 *
 * @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).
 *
 * @param date - The date to be changed
 * @param weekYear - The local week-numbering year of the new date
 * @param options - An object with options
 *
 * @returns The new date with the local week-numbering year set
 *
 * @example
 * // Set the local week-numbering year 2004 to 2 January 2010 with default options:
 * const result = setWeekYear(new Date(2010, 0, 2), 2004)
 * //=> Sat Jan 03 2004 00:00:00
 *
 * @example
 * // Set the local week-numbering year 2004 to 2 January 2010,
 * // if Monday is the first day of week
 * // and 4 January is always in the first week of the year:
 * const result = setWeekYear(new Date(2010, 0, 2), 2004, {
 *   weekStartsOn: 1,
 *   firstWeekContainsDate: 4
 * })
 * //=> Sat Jan 01 2005 00:00:00
 */
export declare function setWeekYear<DateType extends Date>(
  date: DateType | number | string,
  weekYear: number,
  options?: SetWeekYearOptions,
): DateType;