In Javascript/Nodejs I typed x=new Date(2010,0,1) This will mean 1st Jan 2010. But I see 2009-12-31T18:30:00.000Z in the output. What could be the reason for that?

CodePudding user response：

The missing parameters hour, minute and second are initialised to 0, the entire date is assumed to be your timezone (2010-01-01 00:00:00 India time I assume), and the result you see is being output as UTC date. In other words, when it was midnight Jan 1st 2010 in your timezone, it was Dec. 31st 18:30 UTC.

Why it's being output in UTC depends on your method of printing and/or browser used; it's somewhat free to choose how it will output the date.