Can I make node.js Date always be in UTC/GMT?

Question

My app runs on Linux servers, where the time is (naturally) set to UTC/GMT. However the app is developed on Mac desktops where the time is typically set to a local timezone.

I could change every new Date() in my code to run:

var date = new Date().getTime();

And thus ensure dates on the server are always GMT, but that seems inelegant.

I understand previous versions of node used to always return UTC/GMT. Is there any way to bring this behavior back?

Edit: Removed adding timezone offset to getTime() per comments - since getTime() is already in UTC.

I think that old behavior was just the way the REPL code worked. You can always use the UTC APIs in your own code if you want. — Pointy, Aug 18 '14 at 16:27
@pointy is there any way to make UTC the default when `new Date()` is ran? — mikemaccana, Aug 18 '14 at 16:29
You can *always* get the UTC date from a Date instance. Other than keeping the underlying platform set with UTC as the local time zone, however, I don't know of a way to tell the JavaScript runtime (node) to do that for you. — Pointy, Aug 18 '14 at 16:32
`getTime()` will always return the ms since the epoch in UTC. Adding the current time zone offset is never a good idea. — Matt Johnson-Pint, Aug 18 '14 at 16:39

score 42 · Accepted Answer · edited Jan 31 '19 at 11:34

42

You can use TZ configuration parameter of node.js as follows.

For bash (and related)

export TZ=UTC

For Powershell

$env:TC = 'UTC'

Then for both:

nodejs server/index.js

edited Jan 31 '19 at 11:34

mikemaccana

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answered Mar 09 '16 at 10:20

Er. Mohit Agrawal

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Great, thanks! One note, when running unit tests with Mocha that test dates, I needed to run it like `export TZ=UTC; mocha --recursive test`. Though `export TZ=utc` works to change the time zone to UTC, the CI box writes it uppercased as `UTC` —important if you do a date string assertion. – Tina Jun 11 '16 at 16:51

score 18 · Answer 2 · edited May 26 '22 at 13:10

From the MDN docs on Date#getTime:

The value returned by the getTime method is the number of milliseconds since 1 January 1970 00:00:00 UTC.

Assuming you're storing dates/times as numbers (which I would recommend), getTime is already UTC, always.

Suppose your client then requests a date from the server. If the server provides the date as a number, the client can then do:

new Date(timestamp);

And it will be correctly adjusted to the local time on the client.

Of course, maybe I'm misunderstanding your problem. But I just want to point out that this...

new Date().getTime() + new Date().getTimezoneOffset();

...should never really make sense. It's taking a UTC-based time and then offsetting it further, in essence double-offsetting a time.

Can I make node.js Date always be in UTC/GMT?

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