28 lines
960 B
JavaScript
28 lines
960 B
JavaScript
var getISOYear = require('../get_iso_year/index.js')
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/**
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* @category ISO Week-Numbering Year Helpers
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* @summary Get the number of calendar ISO week-numbering years between the given dates.
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*
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* @description
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* Get the number of calendar ISO week-numbering years between the given dates.
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*
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* ISO week-numbering year: http://en.wikipedia.org/wiki/ISO_week_date
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*
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* @param {Date|String|Number} dateLeft - the later date
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* @param {Date|String|Number} dateRight - the earlier date
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* @returns {Number} the number of calendar ISO week-numbering years
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*
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* @example
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* // How many calendar ISO week-numbering years are 1 January 2010 and 1 January 2012?
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* var result = differenceInCalendarISOYears(
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* new Date(2012, 0, 1),
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* new Date(2010, 0, 1)
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* )
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* //=> 2
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*/
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function differenceInCalendarISOYears (dirtyDateLeft, dirtyDateRight) {
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return getISOYear(dirtyDateLeft) - getISOYear(dirtyDateRight)
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}
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module.exports = differenceInCalendarISOYears
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