code: function formatDate(date) {
              let settings = dateFormat || defaultAxisSettings;
              let format = null;
              let localeOptions = {month:'short', day:'numeric'};
  
              if (settings === axisTimeCombinations.DAY_MONTH || settings === axisTimeCombinations.MONTH_YEAR) {
                  format = monthDayYearFormat;
                  localeOptions.year = 'numeric';
              } else if (settings === axisTimeCombinations.HOUR_DAY || settings === axisTimeCombinations.MINUTE_HOUR) {
                  format = monthDayHourFormat;
                  localeOptions.hour = 'numeric';
              } else if (settings === axisTimeCombinations.CUSTOM && typeof dateCustomFormat === 'string') {
                  format = d3TimeFormat.timeFormat(dateCustomFormat);
              }
  
              if (locale && ((typeof Intl !== 'undefined') && (typeof Intl === 'object' && Intl.DateTimeFormat))) {
                  let f = Intl.DateTimeFormat(locale, localeOptions);
  
                  return f.format(date);
              }
  
              return format(date);
          }
docs: Figures out which date format to use when showing the date of the current data entry
  @param {Date} date   Date object to format
  @return {Function}   The proper date formatting function
  @private