Determines if a given year is a leap year.
Contributed by @itsbrunodev
function isLeapYear(year) {
if (year % 4 !== 0) return false;
if (year % 100 === 0 && year % 400 !== 0) return false;
return true;
}
isLeapYear(2024); // true
isLeapYear(2023); // false