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import addDays from "../addDays/index.js" ;
import toDate from "../toDate/index.js" ;
import toInteger from "../_lib/toInteger/index.js" ;
import requiredArgs from "../_lib/requiredArgs/index.js" ;
/**
* @name setDay
* @category Weekday Helpers
* @summary Set the day of the week to the given date.
*
* @description
* Set the day of the week to the given date.
*
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* ### v2.0.0 breaking changes:
*
* - [Changes that are common for the whole library](https://github.com/date-fns/date-fns/blob/master/docs/upgradeGuide.md#Common-Changes).
*
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* @param {Date|Number} date - the date to be changed
* @param {Number} day - the day of the week of the new date
* @param {Object} [options] - an object with options.
* @param {Locale} [options.locale=defaultLocale] - the locale object. See [Locale]{@link https://date-fns.org/docs/Locale}
* @param {0|1|2|3|4|5|6} [options.weekStartsOn=0] - the index of the first day of the week (0 - Sunday)
* @returns {Date} the new date with the day of the week set
* @throws {TypeError} 2 arguments required
* @throws {RangeError} `options.weekStartsOn` must be between 0 and 6
*
* @example
* // Set week day to Sunday, with the default weekStartsOn of Sunday:
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* var result = setDay(new Date(2014, 8, 1), 0)
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* //=> Sun Aug 31 2014 00:00:00
*
* @example
* // Set week day to Sunday, with a weekStartsOn of Monday:
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* var result = setDay(new Date(2014, 8, 1), 0, { weekStartsOn: 1 })
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* //=> Sun Sep 07 2014 00:00:00
*/
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export default function setDay ( dirtyDate , dirtyDay , dirtyOptions ) {
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requiredArgs ( 2 , arguments ) ;
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var options = dirtyOptions || { } ;
var locale = options . locale ;
var localeWeekStartsOn = locale && locale . options && locale . options . weekStartsOn ;
var defaultWeekStartsOn = localeWeekStartsOn == null ? 0 : toInteger ( localeWeekStartsOn ) ;
var weekStartsOn = options . weekStartsOn == null ? defaultWeekStartsOn : toInteger ( options . weekStartsOn ) ; // Test if weekStartsOn is between 0 and 6 _and_ is not NaN
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if ( ! ( weekStartsOn >= 0 && weekStartsOn <= 6 ) ) {
throw new RangeError ( 'weekStartsOn must be between 0 and 6 inclusively' ) ;
}
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var date = toDate ( dirtyDate , options ) ;
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var day = toInteger ( dirtyDay ) ;
var currentDay = date . getDay ( ) ;
var remainder = day % 7 ;
var dayIndex = ( remainder + 7 ) % 7 ;
var delta = 7 - weekStartsOn ;
var diff = day < 0 || day > 6 ? day - ( currentDay + delta ) % 7 : ( dayIndex + delta ) % 7 - ( currentDay + delta ) % 7 ;
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return addDays ( date , diff , options ) ;
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}