35 lines
1.2 KiB
JavaScript
35 lines
1.2 KiB
JavaScript
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var parse = require('../parse/index.js')
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var getDaysInMonth = require('../get_days_in_month/index.js')
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/**
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* @category Month Helpers
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* @summary Add the specified number of months to the given date.
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*
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* @description
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* Add the specified number of months to the given date.
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*
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* @param {Date|String|Number} date - the date to be changed
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* @param {Number} amount - the amount of months to be added
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* @returns {Date} the new date with the months added
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*
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* @example
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* // Add 5 months to 1 September 2014:
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* var result = addMonths(new Date(2014, 8, 1), 5)
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* //=> Sun Feb 01 2015 00:00:00
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*/
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function addMonths (dirtyDate, dirtyAmount) {
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var date = parse(dirtyDate)
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var amount = Number(dirtyAmount)
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var desiredMonth = date.getMonth() + amount
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var dateWithDesiredMonth = new Date(0)
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dateWithDesiredMonth.setFullYear(date.getFullYear(), desiredMonth, 1)
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dateWithDesiredMonth.setHours(0, 0, 0, 0)
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var daysInMonth = getDaysInMonth(dateWithDesiredMonth)
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// Set the last day of the new month
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// if the original date was the last day of the longer month
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date.setMonth(desiredMonth, Math.min(daysInMonth, date.getDate()))
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return date
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}
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module.exports = addMonths
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