📝 Commit Details:

backend/node_modules/date-fns/getWeek.js

@@ -0,0 +1,55 @@
+import { millisecondsInWeek } from "./constants.js";
+import { startOfWeek } from "./startOfWeek.js";
+import { startOfWeekYear } from "./startOfWeekYear.js";
+import { toDate } from "./toDate.js";
+
+/**
+ * The {@link getWeek} function options.
+ */
+
+/**
+ * @name getWeek
+ * @category Week Helpers
+ * @summary Get the local week index of the given date.
+ *
+ * @description
+ * Get the local week index of the given date.
+ * 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
+ *
+ * @param date - The given date
+ * @param options - An object with options
+ *
+ * @returns The week
+ *
+ * @example
+ * // Which week of the local week numbering year is 2 January 2005 with default options?
+ * const result = getWeek(new Date(2005, 0, 2))
+ * //=> 2
+ *
+ * @example
+ * // Which week of the local week numbering year is 2 January 2005,
+ * // if Monday is the first day of the week,
+ * // and the first week of the year always contains 4 January?
+ * const result = getWeek(new Date(2005, 0, 2), {
+ *   weekStartsOn: 1,
+ *   firstWeekContainsDate: 4
+ * })
+ * //=> 53
+ */
+export function getWeek(date, options) {
+  const _date = toDate(date, options?.in);
+  const diff = +startOfWeek(_date, options) - +startOfWeekYear(_date, options);
+
+  // 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 getWeek;