29 lines
1.2 KiB
JavaScript
29 lines
1.2 KiB
JavaScript
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import addISOWeekYears from "../addISOWeekYears/index.js";
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import requiredArgs from "../_lib/requiredArgs/index.js";
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import toInteger from "../_lib/toInteger/index.js";
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/**
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* @name subISOWeekYears
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* @category ISO Week-Numbering Year Helpers
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* @summary Subtract the specified number of ISO week-numbering years from the given date.
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*
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* @description
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* Subtract the specified number of ISO week-numbering years from the given date.
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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|Number} date - the date to be changed
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* @param {Number} amount - the amount of ISO week-numbering years to be subtracted. Positive decimals will be rounded using `Math.floor`, decimals less than zero will be rounded using `Math.ceil`.
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* @returns {Date} the new date with the ISO week-numbering years subtracted
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* @throws {TypeError} 2 arguments required
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*
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* @example
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* // Subtract 5 ISO week-numbering years from 1 September 2014:
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* const result = subISOWeekYears(new Date(2014, 8, 1), 5)
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* //=> Mon Aug 31 2009 00:00:00
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*/
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export default function subISOWeekYears(dirtyDate, dirtyAmount) {
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requiredArgs(2, arguments);
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var amount = toInteger(dirtyAmount);
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return addISOWeekYears(dirtyDate, -amount);
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}
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