Current File : /var/www/html/node_modules/date-fns/esm/differenceInISOWeekYears/index.js
import toDate from "../toDate/index.js";
import differenceInCalendarISOWeekYears from "../differenceInCalendarISOWeekYears/index.js";
import compareAsc from "../compareAsc/index.js";
import subISOWeekYears from "../subISOWeekYears/index.js";
import requiredArgs from "../_lib/requiredArgs/index.js";
/**
* @name differenceInISOWeekYears
* @category ISO Week-Numbering Year Helpers
* @summary Get the number of full ISO week-numbering years between the given dates.
*
* @description
* Get the number of full ISO week-numbering years between the given dates.
*
* ISO week-numbering year: http://en.wikipedia.org/wiki/ISO_week_date
*
* ### 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).
*
* - The function was renamed from `differenceInISOYears` to `differenceInISOWeekYears`.
* "ISO week year" is short for [ISO week-numbering year](https://en.wikipedia.org/wiki/ISO_week_date).
* This change makes the name consistent with
* locale-dependent week-numbering year helpers, e.g., `addWeekYears`.
*
* @param {Date|Number} dateLeft - the later date
* @param {Date|Number} dateRight - the earlier date
* @returns {Number} the number of full ISO week-numbering years
* @throws {TypeError} 2 arguments required
*
* @example
* // How many full ISO week-numbering years are between 1 January 2010 and 1 January 2012?
* var result = differenceInISOWeekYears(
* new Date(2012, 0, 1),
* new Date(2010, 0, 1)
* )
* //=> 1
*/
export default function differenceInISOWeekYears(dirtyDateLeft, dirtyDateRight) {
requiredArgs(2, arguments);
var dateLeft = toDate(dirtyDateLeft);
var dateRight = toDate(dirtyDateRight);
var sign = compareAsc(dateLeft, dateRight);
var difference = Math.abs(differenceInCalendarISOWeekYears(dateLeft, dateRight));
dateLeft = subISOWeekYears(dateLeft, sign * difference); // Math.abs(diff in full ISO years - diff in calendar ISO years) === 1
// if last calendar ISO year is not full
// If so, result must be decreased by 1 in absolute value
var isLastISOWeekYearNotFull = Number(compareAsc(dateLeft, dateRight) === -sign);
var result = sign * (difference - isLastISOWeekYearNotFull); // Prevent negative zero
return result === 0 ? 0 : result;
}
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