Day of next or previous month
Let's find out the day of the week on the first of the previous month. To do this, subtract one from the current month:
let now = new Date();
let date = new Date(now.getFullYear(), now.getMonth() - 1, 1);
console.log(date.getDay());
Question: will there be a problem if
the current month is January? After
all, it has the number 0, and
when subtracting one from it, we get
minus the first month.
Determine what day of the week was a month ago on the same day of the month as today.
