function getMixedMonthName(afterMonthIndex, monthList) {
  var mixedMonthName = null;
  var afterMonthShorthand = getShorthand(monthList[afterMonthIndex].name);
  var beforeMonthShorthand = afterMonthIndex > 0 ? getShorthand(monthList[afterMonthIndex - 1].name) : null;
  var firstMonthShorthand = getShorthand(monthList[0].name);
  var lastMonthShorthand = getShorthand(monthList[monthList.length - 1].name);

  if (afterMonthIndex > 0) {
    mixedMonthName = "".concat(beforeMonthShorthand, "/").concat(afterMonthShorthand);
  } else if (afterMonthIndex === monthList.length - 1) {
    mixedMonthName = "".concat(afterMonthShorthand, "/").concat(firstMonthShorthand);
  } else {
    mixedMonthName = "".concat(lastMonthShorthand, "/").concat(afterMonthShorthand);
  }

  return mixedMonthName;
}
Generate the name for a mixed month.

@private
@param {Number} afterMonthIndex Index of the month after the mixed one.
@param {Array} monthList List of the months.
@returns {String} Name for the mixed month.