code: function isSelectable(minDate, maxDate, date) {
    if (
      (minDate && isBefore(date, minDate)) ||
      (maxDate && isBefore(maxDate, date))
    ) {
      return false;
    }
    return true;
  }
docs: Checks to see if the date given is
  between the min and max dates.
  @param {Date} minDate The earliest date available
  @param {Date} maxDate The furthest date available
  @param {Date} date The date to compare with
  @returns {Boolean} Whether the date is between min and max date