📝 Commit Details:

backend/node_modules/date-fns/differenceInDays.js

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+import { normalizeDates } from "./_lib/normalizeDates.js";
+import { differenceInCalendarDays } from "./differenceInCalendarDays.js";
+
+/**
+ * The {@link differenceInDays} function options.
+ */
+
+/**
+ * @name differenceInDays
+ * @category Day Helpers
+ * @summary Get the number of full days between the given dates.
+ *
+ * @description
+ * Get the number of full day periods between two dates. Fractional days are
+ * truncated towards zero.
+ *
+ * One "full day" is the distance between a local time in one day to the same
+ * local time on the next or previous day. A full day can sometimes be less than
+ * or more than 24 hours if a daylight savings change happens between two dates.
+ *
+ * To ignore DST and only measure exact 24-hour periods, use this instead:
+ * `Math.trunc(differenceInHours(dateLeft, dateRight)/24)|0`.
+ *
+ * @param laterDate - The later date
+ * @param earlierDate - The earlier date
+ * @param options - An object with options
+ *
+ * @returns The number of full days according to the local timezone
+ *
+ * @example
+ * // How many full days are between
+ * // 2 July 2011 23:00:00 and 2 July 2012 00:00:00?
+ * const result = differenceInDays(
+ *   new Date(2012, 6, 2, 0, 0),
+ *   new Date(2011, 6, 2, 23, 0)
+ * )
+ * //=> 365
+ *
+ * @example
+ * // How many full days are between
+ * // 2 July 2011 23:59:00 and 3 July 2011 00:01:00?
+ * const result = differenceInDays(
+ *   new Date(2011, 6, 3, 0, 1),
+ *   new Date(2011, 6, 2, 23, 59)
+ * )
+ * //=> 0
+ *
+ * @example
+ * // How many full days are between
+ * // 1 March 2020 0:00 and 1 June 2020 0:00 ?
+ * // Note: because local time is used, the
+ * // result will always be 92 days, even in
+ * // time zones where DST starts and the
+ * // period has only 92*24-1 hours.
+ * const result = differenceInDays(
+ *   new Date(2020, 5, 1),
+ *   new Date(2020, 2, 1)
+ * )
+ * //=> 92
+ */
+export function differenceInDays(laterDate, earlierDate, options) {
+  const [laterDate_, earlierDate_] = normalizeDates(
+    options?.in,
+    laterDate,
+    earlierDate,
+  );
+
+  const sign = compareLocalAsc(laterDate_, earlierDate_);
+  const difference = Math.abs(
+    differenceInCalendarDays(laterDate_, earlierDate_),
+  );
+
+  laterDate_.setDate(laterDate_.getDate() - sign * difference);
+
+  // Math.abs(diff in full days - diff in calendar days) === 1 if last calendar day is not full
+  // If so, result must be decreased by 1 in absolute value
+  const isLastDayNotFull = Number(
+    compareLocalAsc(laterDate_, earlierDate_) === -sign,
+  );
+
+  const result = sign * (difference - isLastDayNotFull);
+  // Prevent negative zero
+  return result === 0 ? 0 : result;
+}
+
+// Like `compareAsc` but uses local time not UTC, which is needed
+// for accurate equality comparisons of UTC timestamps that end up
+// having the same representation in local time, e.g. one hour before
+// DST ends vs. the instant that DST ends.
+function compareLocalAsc(laterDate, earlierDate) {
+  const diff =
+    laterDate.getFullYear() - earlierDate.getFullYear() ||
+    laterDate.getMonth() - earlierDate.getMonth() ||
+    laterDate.getDate() - earlierDate.getDate() ||
+    laterDate.getHours() - earlierDate.getHours() ||
+    laterDate.getMinutes() - earlierDate.getMinutes() ||
+    laterDate.getSeconds() - earlierDate.getSeconds() ||
+    laterDate.getMilliseconds() - earlierDate.getMilliseconds();
+
+  if (diff < 0) return -1;
+  if (diff > 0) return 1;
+
+  // Return 0 if diff is 0; return NaN if diff is NaN
+  return diff;
+}
+
+// Fallback for modularized imports:
+export default differenceInDays;