46 lines
1.9 KiB
JavaScript
46 lines
1.9 KiB
JavaScript
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import getTimezoneOffsetInMilliseconds from "../_lib/getTimezoneOffsetInMilliseconds/index.js";
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import startOfDay from "../startOfDay/index.js";
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import requiredArgs from "../_lib/requiredArgs/index.js";
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var MILLISECONDS_IN_DAY = 86400000;
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/**
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* @name differenceInCalendarDays
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* @category Day Helpers
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* @summary Get the number of calendar days between the given dates.
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*
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* @description
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* Get the number of calendar days between the given dates. This means that the times are removed
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* from the dates and then the difference in days is calculated.
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*
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* @param {Date|Number} dateLeft - the later date
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* @param {Date|Number} dateRight - the earlier date
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* @returns {Number} the number of calendar days
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* @throws {TypeError} 2 arguments required
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*
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* @example
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* // How many calendar days are between
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* // 2 July 2011 23:00:00 and 2 July 2012 00:00:00?
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* const result = differenceInCalendarDays(
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* new Date(2012, 6, 2, 0, 0),
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* new Date(2011, 6, 2, 23, 0)
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* )
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* //=> 366
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* // How many calendar days are between
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* // 2 July 2011 23:59:00 and 3 July 2011 00:01:00?
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* const result = differenceInCalendarDays(
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* new Date(2011, 6, 3, 0, 1),
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* new Date(2011, 6, 2, 23, 59)
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* )
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* //=> 1
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*/
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export default function differenceInCalendarDays(dirtyDateLeft, dirtyDateRight) {
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requiredArgs(2, arguments);
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var startOfDayLeft = startOfDay(dirtyDateLeft);
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var startOfDayRight = startOfDay(dirtyDateRight);
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var timestampLeft = startOfDayLeft.getTime() - getTimezoneOffsetInMilliseconds(startOfDayLeft);
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var timestampRight = startOfDayRight.getTime() - getTimezoneOffsetInMilliseconds(startOfDayRight); // Round the number of days to the nearest integer
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// because the number of milliseconds in a day is not constant
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// (e.g. it's different in the day of the daylight saving time clock shift)
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return Math.round((timestampLeft - timestampRight) / MILLISECONDS_IN_DAY);
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}
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