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 王天杨
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import { constructFrom } from "./constructFrom.mjs";
import { getWeekYear } from "./getWeekYear.mjs";
import { startOfWeek } from "./startOfWeek.mjs";
import { getDefaultOptions } from "./_lib/defaultOptions.mjs";
/**
* The {@link startOfWeekYear} function options.
*/
/**
* @name startOfWeekYear
* @category Week-Numbering Year Helpers
* @summary Return the start of a local week-numbering year for the given date.
*
* @description
* Return the start of a local week-numbering year.
* 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 original date
* @param options - An object with options
*
* @returns The start of a week-numbering year
*
* @example
* // The start of an a week-numbering year for 2 July 2005 with default settings:
* const result = startOfWeekYear(new Date(2005, 6, 2))
* //=> Sun Dec 26 2004 00:00:00
*
* @example
* // The start of a week-numbering year for 2 July 2005
* // if Monday is the first day of week
* // and 4 January is always in the first week of the year:
* const result = startOfWeekYear(new Date(2005, 6, 2), {
* weekStartsOn: 1,
* firstWeekContainsDate: 4
* })
* //=> Mon Jan 03 2005 00:00:00
*/
export function startOfWeekYear(date, options) {
const defaultOptions = getDefaultOptions();
const firstWeekContainsDate =
options?.firstWeekContainsDate ??
options?.locale?.options?.firstWeekContainsDate ??
defaultOptions.firstWeekContainsDate ??
defaultOptions.locale?.options?.firstWeekContainsDate ??
1;
const year = getWeekYear(date, options);
const firstWeek = constructFrom(date, 0);
firstWeek.setFullYear(year, 0, firstWeekContainsDate);
firstWeek.setHours(0, 0, 0, 0);
const _date = startOfWeek(firstWeek, options);
return _date;
}
// Fallback for modularized imports:
export default startOfWeekYear;
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