main repo

node_modules/date-fns/differenceInCalendarDays.mjs

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+import { millisecondsInDay } from "./constants.mjs";
+import { startOfDay } from "./startOfDay.mjs";
+import { getTimezoneOffsetInMilliseconds } from "./_lib/getTimezoneOffsetInMilliseconds.mjs";
+
+/**
+ * @name differenceInCalendarDays
+ * @category Day Helpers
+ * @summary Get the number of calendar days between the given dates.
+ *
+ * @description
+ * Get the number of calendar days between the given dates. This means that the times are removed
+ * from the dates and then the difference in days is calculated.
+ *
+ * @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 dateLeft - The later date
+ * @param dateRight - The earlier date
+ *
+ * @returns The number of calendar days
+ *
+ * @example
+ * // How many calendar days are between
+ * // 2 July 2011 23:00:00 and 2 July 2012 00:00:00?
+ * const result = differenceInCalendarDays(
+ *   new Date(2012, 6, 2, 0, 0),
+ *   new Date(2011, 6, 2, 23, 0)
+ * )
+ * //=> 366
+ * // How many calendar days are between
+ * // 2 July 2011 23:59:00 and 3 July 2011 00:01:00?
+ * const result = differenceInCalendarDays(
+ *   new Date(2011, 6, 3, 0, 1),
+ *   new Date(2011, 6, 2, 23, 59)
+ * )
+ * //=> 1
+ */
+export function differenceInCalendarDays(dateLeft, dateRight) {
+  const startOfDayLeft = startOfDay(dateLeft);
+  const startOfDayRight = startOfDay(dateRight);
+
+  const timestampLeft =
+    +startOfDayLeft - getTimezoneOffsetInMilliseconds(startOfDayLeft);
+  const timestampRight =
+    +startOfDayRight - getTimezoneOffsetInMilliseconds(startOfDayRight);
+
+  // Round the number of days to the nearest integer because the number of
+  // milliseconds in a day is not constant (e.g. it's different in the week of
+  // the daylight saving time clock shift).
+  return Math.round((timestampLeft - timestampRight) / millisecondsInDay);
+}
+
+// Fallback for modularized imports:
+export default differenceInCalendarDays;