code: function adjustDayOfMonth(self) {
          var fields = self.fields;
          var year = fields[YEAR];
          var month = fields[MONTH];
          var monthLen = getMonthLength(year, month);
          var dayOfMonth = fields[DAY_OF_MONTH];
          if (dayOfMonth > monthLen) {
              self.set(DAY_OF_MONTH, monthLen);
          }
      }
docs: ------------------- private start ------------------- private start