firstDayInPreviousWeek method

DateTime firstDayInPreviousWeek([
  1. int firstWeekDay = 1
])

上周第一天

firstWeekDay - 设置每周起始日, assert(firstWeekDay > 0 && firstWeekDay < 7)

Implementation

DateTime firstDayInPreviousWeek([int firstWeekDay = 1]) {
  assert(firstWeekDay > 0 && firstWeekDay < 7);

  return this.subtract(Duration(days: 7)).firstDayInWeek(firstWeekDay);
}