code: function (nthWeek, day, range) {
          var rangeInfo = this._getRangeInfo(range);
  
          if (nthWeek > rangeInfo.weeks
              || (nthWeek === 0 && day < rangeInfo.fweek)
              || (nthWeek === rangeInfo.weeks && day > rangeInfo.lweek)
          ) {
              return false;
          }
  
          var nthDay = (nthWeek - 1) * 7 - rangeInfo.fweek + day;
          var date = new Date(rangeInfo.start.time);
          date.setDate(rangeInfo.start.d + nthDay);
  
          return this.getDateInfo(date);
      }
docs: get date by nthWeeks and week day in range
  
  @private
  @param  {number} nthWeek the week
  @param  {number} day   the week day
  @param  {Array} range [d1, d2]
  @return {Object}