function startOfWeek(dirtyDate, dirtyOptions) {
  __WEBPACK_IMPORTED_MODULE_2__lib_requiredArgs_index_js__["a" /* default */](1, arguments);
  var options = dirtyOptions || {};
  var locale = options.locale;
  var localeWeekStartsOn = locale && locale.options && locale.options.weekStartsOn;
  var defaultWeekStartsOn = localeWeekStartsOn == null ? 0 : __WEBPACK_IMPORTED_MODULE_1__lib_toInteger_index_js__["a" /* default */](localeWeekStartsOn);
  var weekStartsOn = options.weekStartsOn == null ? defaultWeekStartsOn : __WEBPACK_IMPORTED_MODULE_1__lib_toInteger_index_js__["a" /* default */](options.weekStartsOn); // Test if weekStartsOn is between 0 and 6 _and_ is not NaN

  if (!(weekStartsOn >= 0 && weekStartsOn <= 6)) {
    throw new RangeError('weekStartsOn must be between 0 and 6 inclusively');
  }

  var date = __WEBPACK_IMPORTED_MODULE_0__toDate_index_js__["a" /* default */](dirtyDate);
  var day = date.getDay();
  var diff = (day < weekStartsOn ? 7 : 0) + day - weekStartsOn;
  date.setDate(date.getDate() - diff);
  date.setHours(0, 0, 0, 0);
  return date;
}
@name startOfWeek
@category Week Helpers
@summary Return the start of a week for the given date.

@description
Return the start of a week for the given date.
The result will be in the local timezone.

### 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).

@param {Date|Number} date - the original 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 start of a week
@throws {TypeError} 1 argument required
@throws {RangeError} `options.weekStartsOn` must be between 0 and 6

@example
// The start of a week for 2 September 2014 11:55:00:
var result = startOfWeek(new Date(2014, 8, 2, 11, 55, 0))
//=> Sun Aug 31 2014 00:00:00

@example
// If the week starts on Monday, the start of the week for 2 September 2014 11:55:00:
var result = startOfWeek(new Date(2014, 8, 2, 11, 55, 0), { weekStartsOn: 1 })
//=> Mon Sep 01 2014 00:00:00