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- import { millisecondsInWeek } from "./constants.js";
- import { startOfISOWeek } from "./startOfISOWeek.js";
- import { startOfISOWeekYear } from "./startOfISOWeekYear.js";
- import { toDate } from "./toDate.js";
- /**
- * The {@link getISOWeek} function options.
- */
- /**
- * @name getISOWeek
- * @category ISO Week Helpers
- * @summary Get the ISO week of the given date.
- *
- * @description
- * Get the ISO week of the given date.
- *
- * ISO week-numbering year: http://en.wikipedia.org/wiki/ISO_week_date
- *
- * @param date - The given date
- * @param options - The options
- *
- * @returns The ISO week
- *
- * @example
- * // Which week of the ISO-week numbering year is 2 January 2005?
- * const result = getISOWeek(new Date(2005, 0, 2))
- * //=> 53
- */
- export function getISOWeek(date, options) {
- const _date = toDate(date, options?.in);
- const diff = +startOfISOWeek(_date) - +startOfISOWeekYear(_date);
- // Round the number of weeks to the nearest integer because the number of
- // milliseconds in a week is not constant (e.g. it's different in the week of
- // the daylight saving time clock shift).
- return Math.round(diff / millisecondsInWeek) + 1;
- }
- // Fallback for modularized imports:
- export default getISOWeek;
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