code: function(options, $input, columnName) {
          var datePicker = this.datePickerMap[columnName];
          var format = options.format || DEFAULT_DATE_FORMAT;
          var date = options.date || (new Date());
          var selectableRanges = options.selectableRanges;
  
          datePicker.setInput($input, {
              format: format,
              syncFromInput: true
          });
  
          if (selectableRanges) {
              datePicker.setRanges(selectableRanges);
          } else {
              datePicker.setRanges(FULL_RANGES);
          }
  
          if ($input.val() === '') {
              datePicker.setDate(date);
              $input.val('');
          }
      }
docs: Resets date picker options
  @param {Object} options - datePicker options
  @param {jQuery} $input - target input element
  @param {string} columnName - name to find the DatePicker instance created on each column
  @private