const monthDays = useMemo(() => {
const monthDays = new Array(42)
.fill(null)
.map((_, index) => index + 1)
.map(elem => (elem >= monthFirstDay && elem < monthDaysCount + monthFirstDay ? elem - monthFirstDay + 1 : null))
return new Array(6)
.fill([])
.map((_, arrIndex) => new Array(7).fill(null).map((_, elemIndex) => monthDays[elemIndex + 7 * arrIndex]))
}, [monthDaysCount])