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					68 lines
				
				2.7 KiB
			
		
		
			
		
	
	
					68 lines
				
				2.7 KiB
			| 
											3 years ago
										 | "use strict"; | ||
|  | 
 | ||
|  | Object.defineProperty(exports, "__esModule", { | ||
|  |   value: true | ||
|  | }); | ||
|  | exports.default = differenceInISOWeekYears; | ||
|  | 
 | ||
|  | var _index = _interopRequireDefault(require("../toDate/index.js")); | ||
|  | 
 | ||
|  | var _index2 = _interopRequireDefault(require("../differenceInCalendarISOWeekYears/index.js")); | ||
|  | 
 | ||
|  | var _index3 = _interopRequireDefault(require("../compareAsc/index.js")); | ||
|  | 
 | ||
|  | var _index4 = _interopRequireDefault(require("../subISOWeekYears/index.js")); | ||
|  | 
 | ||
|  | var _index5 = _interopRequireDefault(require("../_lib/requiredArgs/index.js")); | ||
|  | 
 | ||
|  | function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; } | ||
|  | 
 | ||
|  | /** | ||
|  |  * @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
 | ||
|  |  */ | ||
|  | function differenceInISOWeekYears(dirtyDateLeft, dirtyDateRight) { | ||
|  |   (0, _index5.default)(2, arguments); | ||
|  |   var dateLeft = (0, _index.default)(dirtyDateLeft); | ||
|  |   var dateRight = (0, _index.default)(dirtyDateRight); | ||
|  |   var sign = (0, _index3.default)(dateLeft, dateRight); | ||
|  |   var difference = Math.abs((0, _index2.default)(dateLeft, dateRight)); | ||
|  |   dateLeft = (0, _index4.default)(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 = (0, _index3.default)(dateLeft, dateRight) === -sign; | ||
|  |   var result = sign * (difference - isLastISOWeekYearNotFull); // Prevent negative zero
 | ||
|  | 
 | ||
|  |   return result === 0 ? 0 : result; | ||
|  | } | ||
|  | 
 | ||
|  | module.exports = exports.default; |