# 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.

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