lastDayInNextMonth method

DateTime lastDayInNextMonth([
  1. int firstDay = 1
])

下月最后一天

firstDay - 每月起算日期，assert(firstDay > 0 && firstDay < 29)

Implementation

DateTime lastDayInNextMonth([int firstDay = 1]) {
  return firstDayInNextMonth(firstDay).lastDayInMonth(firstDay);
}