go integration and wikipedia

frontend/node_modules/date-fns/getISODay.mjs

@@ -0,0 +1,37 @@
+import { toDate } from "./toDate.mjs";
+
+/**
+ * @name getISODay
+ * @category Weekday Helpers
+ * @summary Get the day of the ISO week of the given date.
+ *
+ * @description
+ * Get the day of the ISO week of the given date,
+ * which is 7 for Sunday, 1 for Monday etc.
+ *
+ * ISO week-numbering year: http://en.wikipedia.org/wiki/ISO_week_date
+ *
+ * @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 given date
+ *
+ * @returns The day of ISO week
+ *
+ * @example
+ * // Which day of the ISO week is 26 February 2012?
+ * const result = getISODay(new Date(2012, 1, 26))
+ * //=> 7
+ */
+export function getISODay(date) {
+  const _date = toDate(date);
+  let day = _date.getDay();
+
+  if (day === 0) {
+    day = 7;
+  }
+
+  return day;
+}
+
+// Fallback for modularized imports:
+export default getISODay;