Source: setWeek/index.js

  1. import getWeek from '../getWeek/index'
  2. import toDate from '../toDate/index'
  3. import toInteger from '../_lib/toInteger/index'
  4. import requiredArgs from '../_lib/requiredArgs/index'
  6. /**
  7.  * @name setWeek
  8.  * @category Week Helpers
  9.  * @summary Set the local week to the given date.
  10.  *
  11.  * @description
  12.  * Set the local week to the given date, saving the weekday number.
  13.  * The exact calculation depends on the values of
  14.  * `options.weekStartsOn` (which is the index of the first day of the week)
  15.  * and `options.firstWeekContainsDate` (which is the day of January, which is always in
  16.  * the first week of the week-numbering year)
  17.  *
  18.  * Week numbering: https://en.wikipedia.org/wiki/Week#Week_numbering
  19.  *
  20.  * ### v2.0.0 breaking changes:
  21.  *
  22.  * - [Changes that are common for the whole library](https://github.com/date-fns/date-fns/blob/master/docs/upgradeGuide.md#Common-Changes).
  23.  *
  24.  * @param {Date|Number} date - the date to be changed
  25.  * @param {Number} week - the week of the new date
  26.  * @param {Object} [options] - an object with options.
  27.  * @param {Locale} [options.locale=defaultLocale] - the locale object. See [Locale]{@link https://date-fns.org/docs/Locale}
  28.  * @param {0|1|2|3|4|5|6} [options.weekStartsOn=0] - the index of the first day of the week (0 - Sunday)
  29.  * @param {1|2|3|4|5|6|7} [options.firstWeekContainsDate=1] - the day of January, which is always in the first week of the year
  30.  * @returns {Date} the new date with the local week set
  31.  * @throws {TypeError} 2 arguments required
  32.  * @throws {RangeError} `options.weekStartsOn` must be between 0 and 6
  33.  * @throws {RangeError} `options.firstWeekContainsDate` must be between 1 and 7
  34.  *
  35.  * @example
  36.  * // Set the 1st week to 2 January 2005 with default options:
  37.  * var result = setWeek(new Date(2005, 0, 2), 1)
  38.  * //=> Sun Dec 26 2004 00:00:00
  39.  *
  40.  * @example
  41.  * // Set the 1st week to 2 January 2005,
  42.  * // if Monday is the first day of the week,
  43.  * // and the first week of the year always contains 4 January:
  44.  * var result = setWeek(new Date(2005, 0, 2), 1, {
  45.  *   weekStartsOn: 1,
  46.  *   firstWeekContainsDate: 4
  47.  * })
  48.  * //=> Sun Jan 4 2004 00:00:00
  49.  */
  50. export default function setWeek(dirtyDate, dirtyWeek, dirtyOptions) {
  51.   requiredArgs(2, arguments)
  53.   var date = toDate(dirtyDate)
  54.   var week = toInteger(dirtyWeek)
  55.   var diff = getWeek(date, dirtyOptions) - week
  56.   date.setDate(date.getDate() - diff * 7)
  57.   return date
  58. }