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- import { getTimezoneOffsetInMilliseconds } from "./_lib/getTimezoneOffsetInMilliseconds.js";
- import { normalizeDates } from "./_lib/normalizeDates.js";
- import { millisecondsInDay } from "./constants.js";
- import { startOfDay } from "./startOfDay.js";
- /**
- * The {@link differenceInCalendarDays} function options.
- */
- /**
- * @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.
- *
- * @param laterDate - The later date
- * @param earlierDate - The earlier date
- * @param options - The options object
- *
- * @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(laterDate, earlierDate, options) {
- const [laterDate_, earlierDate_] = normalizeDates(
- options?.in,
- laterDate,
- earlierDate,
- );
- const laterStartOfDay = startOfDay(laterDate_);
- const earlierStartOfDay = startOfDay(earlierDate_);
- const laterTimestamp =
- +laterStartOfDay - getTimezoneOffsetInMilliseconds(laterStartOfDay);
- const earlierTimestamp =
- +earlierStartOfDay - getTimezoneOffsetInMilliseconds(earlierStartOfDay);
- // 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((laterTimestamp - earlierTimestamp) / millisecondsInDay);
- }
- // Fallback for modularized imports:
- export default differenceInCalendarDays;
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