Q:

Why does new Date(year,month,day) not return an equivialent Date?

one day I fiddled with vanilla NodeJS using the node command line tool. (I am using node v13.11.0)
I tried to create a new Date at the 01.01.1970. I used the usual new Date(year, month, day) constructor. 
As simple as it sounds, I entered new Date(1970, 1, 1) and found out, that it does not return 1970-01-01T00:00:00.0000Z. Instead, it returns 1970-01-31T12:00:00.000Z. 
Has anyone an Idea, why this constructor does not return the equivalent date?

A:

The constructor does more or less what you think:
x = new Date(1970,1,1)
1970-01-31T14:00:00.000Z
> x.getMonth()
1
> x.getDate()
1
> x.getHours()
0

(Note that months count from zero, so you requested the 1st of February).
But if you display the whole date as a string, it's showing the time in UTC, which might not be what you expect.

