index.js
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import isWeekend from '../isWeekend/index.js';
import toDate from '../toDate/index.js';
import toInteger from '../_lib/toInteger/index.js';
import requiredArgs from '../_lib/requiredArgs/index.js';
import isSunday from '../isSunday/index.js';
import isSaturday from '../isSaturday/index.js';
/**
* @name addBusinessDays
* @category Day Helpers
* @summary Add the specified number of business days (mon - fri) to the given date.
*
* @description
* Add the specified number of business days (mon - fri) to the given date, ignoring weekends.
*
* @param {Date|Number} date - the date to be changed
* @param {Number} amount - the amount of business days to be added. Positive decimals will be rounded using `Math.floor`, decimals less than zero will be rounded using `Math.ceil`.
* @returns {Date} the new date with the business days added
* @throws {TypeError} 2 arguments required
*
* @example
* // Add 10 business days to 1 September 2014:
* var result = addBusinessDays(new Date(2014, 8, 1), 10)
* //=> Mon Sep 15 2014 00:00:00 (skipped weekend days)
*/
export default function addBusinessDays(dirtyDate, dirtyAmount) {
requiredArgs(2, arguments);
var date = toDate(dirtyDate);
var startedOnWeekend = isWeekend(date);
var amount = toInteger(dirtyAmount);
if (isNaN(amount)) return new Date(NaN);
var hours = date.getHours();
var sign = amount < 0 ? -1 : 1;
var fullWeeks = toInteger(amount / 5);
date.setDate(date.getDate() + fullWeeks * 7); // Get remaining days not part of a full week
var restDays = Math.abs(amount % 5); // Loops over remaining days
while (restDays > 0) {
date.setDate(date.getDate() + sign);
if (!isWeekend(date)) restDays -= 1;
} // If the date is a weekend day and we reduce a dividable of
// 5 from it, we land on a weekend date.
// To counter this, we add days accordingly to land on the next business day
if (startedOnWeekend && isWeekend(date) && amount !== 0) {
// If we're reducing days, we want to add days until we land on a weekday
// If we're adding days we want to reduce days until we land on a weekday
if (isSaturday(date)) date.setDate(date.getDate() + (sign < 0 ? 2 : -1));
if (isSunday(date)) date.setDate(date.getDate() + (sign < 0 ? 1 : -2));
} // Restore hours to avoid DST lag
date.setHours(hours);
return date;
}