58 lines
1.8 KiB
JavaScript
58 lines
1.8 KiB
JavaScript
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"use strict";
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exports.differenceInMonths = differenceInMonths;
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var _index = require("./_lib/normalizeDates.cjs");
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var _index2 = require("./compareAsc.cjs");
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var _index3 = require("./differenceInCalendarMonths.cjs");
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var _index4 = require("./isLastDayOfMonth.cjs");
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/**
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* The {@link differenceInMonths} function options.
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*/
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/**
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* @name differenceInMonths
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* @category Month Helpers
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* @summary Get the number of full months between the given dates.
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*
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* @param laterDate - The later date
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* @param earlierDate - The earlier date
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* @param options - An object with options
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*
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* @returns The number of full months
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*
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* @example
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* // How many full months are between 31 January 2014 and 1 September 2014?
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* const result = differenceInMonths(new Date(2014, 8, 1), new Date(2014, 0, 31))
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* //=> 7
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*/
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function differenceInMonths(laterDate, earlierDate, options) {
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const [laterDate_, workingLaterDate, earlierDate_] = (0,
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_index.normalizeDates)(options?.in, laterDate, laterDate, earlierDate);
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const sign = (0, _index2.compareAsc)(workingLaterDate, earlierDate_);
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const difference = Math.abs(
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(0, _index3.differenceInCalendarMonths)(workingLaterDate, earlierDate_),
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);
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if (difference < 1) return 0;
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if (workingLaterDate.getMonth() === 1 && workingLaterDate.getDate() > 27)
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workingLaterDate.setDate(30);
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workingLaterDate.setMonth(workingLaterDate.getMonth() - sign * difference);
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let isLastMonthNotFull =
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(0, _index2.compareAsc)(workingLaterDate, earlierDate_) === -sign;
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if (
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(0, _index4.isLastDayOfMonth)(laterDate_) &&
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difference === 1 &&
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(0, _index2.compareAsc)(laterDate_, earlierDate_) === 1
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) {
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isLastMonthNotFull = false;
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}
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const result = sign * (difference - +isLastMonthNotFull);
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return result === 0 ? 0 : result;
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}
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