openingHoursDiff.js

const openingHoursDiff = (workHours, date) => {
  
  let [currentHour, currentMinute] = [date.getHours(), date.getMinutes()]
  let current = currentHour * 100 + currentMinute
  
  let {open, close} = workHours
  let [openHour,  openMinute]  = [Math.floor(open  / 100), open  % 100]
  let [closeHour, closeMinute] = [Math.floor(close / 100), close % 100]
  
  let openMidnight = openHour == 0 && currentHour == 23
  openHour = openMidnight ? 24 : openHour
  let opening  = openMidnight ? 24 * 100 + openMinute  : open

  let closeMidnight = closeHour == 0 && currentHour == 23
  closeHour = closeMidnight ? 24 : closeHour
  let closing   = closeMidnight ? 24 * 100 + closeMinute : close
  
    
  switch(true) {
    case (opening - 100 == current): 
    return `Opens in 1 hour`

    case (opening - 100 < current) && (current < opening): 
    return `Opens in ${ openMinute - currentMinute + (openHour==currentHour?0:60) } minutes`
          
    case (opening <= current) && (current < closing - 100): 
    return `Open`

    case (closing - 100 < current) && (current < closing): 
    return `Closes in ${ closeMinute- currentMinute + (closeHour==currentHour?0:60) } minutes`

    case (closing - 100 == current): 
    return `Closes in 1 hour`
      
    case true:
    return `Closed`
  }
}

openingHoursDiff({open: 900, close:1830}, new Date('08.23.2024 7:59'))
// 'Closed'
openingHoursDiff({open: 900, close:1830}, new Date('08.23.2024 8:00'))
// 'Opens in 1 hour'
openingHoursDiff({open: 900, close:1830}, new Date('08.23.2024 8:01'))
// 'Opens in 59 minutes'
openingHoursDiff({open: 900, close:1830}, new Date('08.23.2024 8:30'))
// 'Opens in 30 minutes'
openingHoursDiff({open: 900, close:1830}, new Date('08.23.2024 8:59'))
// 'Opens in 1 minutes'
openingHoursDiff({open: 900, close:1830}, new Date('08.23.2024 9:00'))
// 'Open'
openingHoursDiff({open: 900, close:1830}, new Date('08.23.2024 17:29'))
// 'Open'
openingHoursDiff({open: 900, close:1830}, new Date('08.23.2024 17:30'))
// 'Closes in 1 hour'
openingHoursDiff({open: 900, close:1830}, new Date('08.23.2024 17:31'))
// 'Closes in 59 minutes'
openingHoursDiff({open: 900, close:1830}, new Date('08.23.2024 18:00'))
// 'Closes in 30 minutes'
openingHoursDiff({open: 900, close:1830}, new Date('08.23.2024 18:29'))
// 'Closes in 1 minutes'
openingHoursDiff({open: 900, close:1830}, new Date('08.23.2024 18:30'))
// 'Closed'
openingHoursDiff({open: 900, close:1830}, new Date('08.23.2024 00:00'))
// 'Closed'

openingHoursDiff({open: 1830, close:30}, new Date('08.23.2024 23:29'))
// 'Open'
openingHoursDiff({open: 1830, close:30}, new Date('08.23.2024 23:30'))
// 'Closes in 1 hour'
openingHoursDiff({open: 1830, close:30}, new Date('08.23.2024 23:31'))
// 'Closes in 59 minutes'
openingHoursDiff({open: 1830, close:30}, new Date('08.23.2024 00:00'))
// 'Closes in 30 minutes'
openingHoursDiff({open: 1830, close:30}, new Date('08.23.2024 00:29'))
// 'Closes in 1 minutes'
openingHoursDiff({open: 1830, close:30}, new Date('08.23.2024 00:30'))
// 'Closed'