Descriptive variables instead of complex conditions

// before: it’s hard to see what this combination of conditions does
if (!(currentDay === 'Saturday' || currentDay === 'Sunday') &&
    currentHour >= 9 && currentHour <= 18) {
  return 'The store is open!'
}


// after: by assigning the conditions to variables, we can use their names
// to explain the logic behind our code in plain language
const isSaturday = currentDay === 'Saturday'
const isSunday = currentDay === 'Sunday'

const isWeekend = isSaturday || isSunday

const isDuringBusinessHours = currentHour >= 9 && currentHour <= 18

if (!isWeekend && isDuringBusinessHours) {
  return 'The store is open!'
}