Determine if a JavaScript date is a weekday or weekend

I've often found myself needing to check if a given date is a weekday or weekend. As I'm not particularly fond of using libraries for such simple tasks, I've come up with a couple of simple helper functions to do the job.

const isWeekday = date => date.getDay() % 6 !== 0;
const isWeekend = date => date.getDay() % 6 === 0;

isWeekday(new Date('2024-01-05')); // true
isWeekend(new Date('2024-01-05')); // false

isWeekday(new Date('2024-01-06')); // false
isWeekend(new Date('2024-01-06')); // true

The entire premise of these snippets is quite simple. We use Date.prototype.getDay() to get the day of the week, which is a number between 0 and 6, where 0 is Sunday and 6 is Saturday. We then use the modulo operator (%) to check if the day is a multiple of 6, which is the case for both Saturday and Sunday. If the remainder is 0, we know the date is a weekend. If the remainder is not 0, we know the date is a weekday.