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天文台pc/tianwentai-ui/node_modules/date-fns/differenceInISOWeekYears.js 1.92 KB
bc518174   王天杨   提交两个项目文件
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  "use strict";
  exports.differenceInISOWeekYears = differenceInISOWeekYears;
  var _index = require("./compareAsc.js");
  var _index2 = require("./differenceInCalendarISOWeekYears.js");
  var _index3 = require("./subISOWeekYears.js");
  var _index4 = require("./toDate.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
   *
   * @typeParam DateType - The `Date` type, the function operates on. Gets inferred from passed arguments. Allows to use extensions like [`UTCDate`](https://github.com/date-fns/utc).
   *
   * @param dateLeft - The later date
   * @param dateRight - The earlier date
   *
   * @returns The number of full ISO week-numbering years
   *
   * @example
   * // How many full ISO week-numbering years are between 1 January 2010 and 1 January 2012?
   * const result = differenceInISOWeekYears(
   *   new Date(2012, 0, 1),
   *   new Date(2010, 0, 1)
   * )
   * //=> 1
   */
  function differenceInISOWeekYears(dateLeft, dateRight) {
    let _dateLeft = (0, _index4.toDate)(dateLeft);
    const _dateRight = (0, _index4.toDate)(dateRight);
  
    const sign = (0, _index.compareAsc)(_dateLeft, _dateRight);
    const difference = Math.abs(
      (0, _index2.differenceInCalendarISOWeekYears)(_dateLeft, _dateRight),
    );
    _dateLeft = (0, _index3.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
    const isLastISOWeekYearNotFull = Number(
      (0, _index.compareAsc)(_dateLeft, _dateRight) === -sign,
    );
    const result = sign * (difference - isLastISOWeekYearNotFull);
    // Prevent negative zero
    return result === 0 ? 0 : result;
  }