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node_modules/date-fns/esm/setISOWeekYear/index.js

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+import toInteger from "../_lib/toInteger/index.js";
+import toDate from "../toDate/index.js";
+import startOfISOWeekYear from "../startOfISOWeekYear/index.js";
+import differenceInCalendarDays from "../differenceInCalendarDays/index.js";
+import requiredArgs from "../_lib/requiredArgs/index.js";
+/**
+ * @name setISOWeekYear
+ * @category ISO Week-Numbering Year Helpers
+ * @summary Set the ISO week-numbering year to the given date.
+ *
+ * @description
+ * Set the ISO week-numbering year to the given date,
+ * saving the week number and the weekday number.
+ *
+ * ISO week-numbering year: http://en.wikipedia.org/wiki/ISO_week_date
+ *
+ * @param {Date|Number} date - the date to be changed
+ * @param {Number} isoWeekYear - the ISO week-numbering year of the new date
+ * @returns {Date} the new date with the ISO week-numbering year set
+ * @throws {TypeError} 2 arguments required
+ *
+ * @example
+ * // Set ISO week-numbering year 2007 to 29 December 2008:
+ * const result = setISOWeekYear(new Date(2008, 11, 29), 2007)
+ * //=> Mon Jan 01 2007 00:00:00
+ */
+export default function setISOWeekYear(dirtyDate, dirtyISOWeekYear) {
+  requiredArgs(2, arguments);
+  var date = toDate(dirtyDate);
+  var isoWeekYear = toInteger(dirtyISOWeekYear);
+  var diff = differenceInCalendarDays(date, startOfISOWeekYear(date));
+  var fourthOfJanuary = new Date(0);
+  fourthOfJanuary.setFullYear(isoWeekYear, 0, 4);
+  fourthOfJanuary.setHours(0, 0, 0, 0);
+  date = startOfISOWeekYear(fourthOfJanuary);
+  date.setDate(date.getDate() + diff);
+  return date;
+}