📝 Commit Details:

backend/node_modules/date-fns/differenceInCalendarWeeks.js

@@ -0,0 +1,61 @@
+import { getTimezoneOffsetInMilliseconds } from "./_lib/getTimezoneOffsetInMilliseconds.js";
+import { normalizeDates } from "./_lib/normalizeDates.js";
+import { millisecondsInWeek } from "./constants.js";
+import { startOfWeek } from "./startOfWeek.js";
+
+/**
+ * The {@link differenceInCalendarWeeks} function options.
+ */
+
+/**
+ * @name differenceInCalendarWeeks
+ * @category Week Helpers
+ * @summary Get the number of calendar weeks between the given dates.
+ *
+ * @description
+ * Get the number of calendar weeks between the given dates.
+ *
+ * @param laterDate - The later date
+ * @param earlierDate - The earlier date
+ * @param options - An object with options.
+ *
+ * @returns The number of calendar weeks
+ *
+ * @example
+ * // How many calendar weeks are between 5 July 2014 and 20 July 2014?
+ * const result = differenceInCalendarWeeks(
+ *   new Date(2014, 6, 20),
+ *   new Date(2014, 6, 5)
+ * )
+ * //=> 3
+ *
+ * @example
+ * // If the week starts on Monday,
+ * // how many calendar weeks are between 5 July 2014 and 20 July 2014?
+ * const result = differenceInCalendarWeeks(
+ *   new Date(2014, 6, 20),
+ *   new Date(2014, 6, 5),
+ *   { weekStartsOn: 1 }
+ * )
+ * //=> 2
+ */
+export function differenceInCalendarWeeks(laterDate, earlierDate, options) {
+  const [laterDate_, earlierDate_] = normalizeDates(
+    options?.in,
+    laterDate,
+    earlierDate,
+  );
+
+  const laterStartOfWeek = startOfWeek(laterDate_, options);
+  const earlierStartOfWeek = startOfWeek(earlierDate_, options);
+
+  const laterTimestamp =
+    +laterStartOfWeek - getTimezoneOffsetInMilliseconds(laterStartOfWeek);
+  const earlierTimestamp =
+    +earlierStartOfWeek - getTimezoneOffsetInMilliseconds(earlierStartOfWeek);
+
+  return Math.round((laterTimestamp - earlierTimestamp) / millisecondsInWeek);
+}
+
+// Fallback for modularized imports:
+export default differenceInCalendarWeeks;