Function formatDateRangeLabel

packages/emcn/src/components/calendar/calendar.tsx:82–104

(
  start: string | Date | undefined,
  end: string | Date | undefined
)

 * to a placeholder.
 */
export function formatDateRangeLabel(
  start: string | Date | undefined,
  end: string | Date | undefined
): string {
  const startDate = parseDateValue(start)
  const endDate = parseDateValue(end)
  if (!startDate && !endDate) return ''
  if (startDate && !endDate) return formatDateLabel(startDate)
  if (!startDate && endDate) return formatDateLabel(endDate)
  if (!startDate || !endDate) return ''
  const sameYear = startDate.getFullYear() === endDate.getFullYear()
  const startLabel = startDate.toLocaleDateString('en-US', {
    month: 'short',
    day: 'numeric',
    ...(sameYear ? {} : { year: 'numeric' }),
  })
  const endLabel = endDate.toLocaleDateString('en-US', {
    year: 'numeric',
    month: 'short',
    day: 'numeric',
  })
  return `${startLabel} - ${endLabel}`
}

function isSameDay(a: Date, b: Date): boolean {
  return (