123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960
import getTimezoneOffsetInMilliseconds from '../_lib/getTimezoneOffsetInMilliseconds/index.js'import startOfDay from '../startOfDay/index.ts'import requiredArgs from '../_lib/requiredArgs/index.ts'
const MILLISECONDS_IN_DAY = 86400000
/** * @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. * * ### v2.0.0 breaking changes: * * - [Changes that are common for the whole library](https://github.com/date-fns/date-fns/blob/master/docs/upgradeGuide.md#Common-Changes). * * @param {Date|Number} dateLeft - the later date * @param {Date|Number} dateRight - the earlier date * @returns {Number} the number of calendar days * @throws {TypeError} 2 arguments required * * @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 default function differenceInCalendarDays(  dirtyDateLeft: Date | number,  dirtyDateRight: Date | number): number {  requiredArgs(2, arguments)
  const startOfDayLeft = startOfDay(dirtyDateLeft)  const startOfDayRight = startOfDay(dirtyDateRight)
  const timestampLeft =    startOfDayLeft.getTime() - getTimezoneOffsetInMilliseconds(startOfDayLeft)  const timestampRight =    startOfDayRight.getTime() - 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 day of the daylight saving time clock shift)  return Math.round((timestampLeft - timestampRight) / MILLISECONDS_IN_DAY)}