FIN INIT

node_modules/date-fns/addMonths.cjs

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+"use strict";
+exports.addMonths = addMonths;
+var _index = require("./constructFrom.cjs");
+var _index2 = require("./toDate.cjs");
+
+/**
+ * The {@link addMonths} function options.
+ */
+
+/**
+ * @name addMonths
+ * @category Month Helpers
+ * @summary Add the specified number of months to the given date.
+ *
+ * @description
+ * Add the specified number of months to the given 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).
+ * @typeParam ResultDate - The result `Date` type, it is the type returned from the context function if it is passed, or inferred from the arguments.
+ *
+ * @param date - The date to be changed
+ * @param amount - The amount of months to be added.
+ * @param options - The options object
+ *
+ * @returns The new date with the months added
+ *
+ * @example
+ * // Add 5 months to 1 September 2014:
+ * const result = addMonths(new Date(2014, 8, 1), 5)
+ * //=> Sun Feb 01 2015 00:00:00
+ *
+ * // Add one month to 30 January 2023:
+ * const result = addMonths(new Date(2023, 0, 30), 1)
+ * //=> Tue Feb 28 2023 00:00:00
+ */
+function addMonths(date, amount, options) {
+  const _date = (0, _index2.toDate)(date, options?.in);
+  if (isNaN(amount)) return (0, _index.constructFrom)(options?.in || date, NaN);
+  if (!amount) {
+    // If 0 months, no-op to avoid changing times in the hour before end of DST
+    return _date;
+  }
+  const dayOfMonth = _date.getDate();
+
+  // The JS Date object supports date math by accepting out-of-bounds values for
+  // month, day, etc. For example, new Date(2020, 0, 0) returns 31 Dec 2019 and
+  // new Date(2020, 13, 1) returns 1 Feb 2021.  This is *almost* the behavior we
+  // want except that dates will wrap around the end of a month, meaning that
+  // new Date(2020, 13, 31) will return 3 Mar 2021 not 28 Feb 2021 as desired. So
+  // we'll default to the end of the desired month by adding 1 to the desired
+  // month and using a date of 0 to back up one day to the end of the desired
+  // month.
+  const endOfDesiredMonth = (0, _index.constructFrom)(
+    options?.in || date,
+    _date.getTime(),
+  );
+  endOfDesiredMonth.setMonth(_date.getMonth() + amount + 1, 0);
+  const daysInMonth = endOfDesiredMonth.getDate();
+  if (dayOfMonth >= daysInMonth) {
+    // If we're already at the end of the month, then this is the correct date
+    // and we're done.
+    return endOfDesiredMonth;
+  } else {
+    // Otherwise, we now know that setting the original day-of-month value won't
+    // cause an overflow, so set the desired day-of-month. Note that we can't
+    // just set the date of `endOfDesiredMonth` because that object may have had
+    // its time changed in the unusual case where where a DST transition was on
+    // the last day of the month and its local time was in the hour skipped or
+    // repeated next to a DST transition.  So we use `date` instead which is
+    // guaranteed to still have the original time.
+    _date.setFullYear(
+      endOfDesiredMonth.getFullYear(),
+      endOfDesiredMonth.getMonth(),
+      dayOfMonth,
+    );
+    return _date;
+  }
+}