@evanxd did you realize that you pass basically the same data for all the calls? and that you are calling `formatDate` multiple times for same value? why not simply do:

```js
var format;

if (isAllDay) {
  format = isOneDay(startDate, endDate) ?
    'one-all-day-duration' :
    'multiple-all-day-duration';
} else {
  format = Calendar.Cal.isSameDate(startDate, endDate) ?
    'one-day-duration' :
    'multiple-day-duration';
}

return _(format, {
  startTime: formatTime(startDate),
  startDate: formatDate(startDate),
  endTime: formatTime(endDate),
  endDate: formatDate(endDate)
});
```

it's way easier to understand and avoid duplication.