Return datetimes in defined timezone

Issue type:

[x] question [ ] bug report [ ] feature request [ ] documentation issue

Database system/driver:

[ ] cordova [ ] mongodb [ ] mssql [ ] mysql / mariadb [ ] oracle [x] postgres [ ] sqlite [ ] sqljs [ ] react-native

TypeORM version:

[x] latest [ ] @next [ ] 0.x.x (or put your version here)

Is it possible to return all timestamps in different defined timezone? For example I save datetimes to postgres timestamp with timezone column, it is saved in UTC as expected. But I would like to return them in different timezone. I tried to set node app like process.env.TZ = "Europe/Prague" but with no success. This only change how datetimes are saved if time offset is not specified.

[chriskalmar]

@pleerock thanks for the nice intro 😎

As for your timezone problem @michalhorcic, I’d love to know why you would like to have timestamps rendered into a specific timezone on the server. UTC is your friend. Imagine having 2 clients - one sitting in New York and one sitting Paris - both receive the same UTC timestamp. Thanks to JavaScript in the browser converting that timestamp into their respective timezone aware local time is as simple as this:

new Date('2018-05-05T10:00:00.000Z')

So all the hard work of figuring out the offsets and doing pointless calculations is taken care of. Plus DST (Daylight saving time) is done automatically as well. (if a government decides one day to stop using DST you won’t have to handle this, because the browser will).

As our world is a complicated place there are timezones on our planet that don’t stick to the full-hour offsets, sometimes you will find 30 minute and even 45 minute offsets (https://en.wikipedia.org/wiki/Time_zone). Another important aspect is that not all browsers work with timezones correctly. So it’s a good idea to resort to dedicated libraries instead. I can recommend 2 of them:

• https://github.com/moment/moment-timezone/
• https://github.com/date-fns/date-fns

Now having said that, there are ways to transform dates into a specific timezone on the server. Postgres has all the tools you need. Here is an example of how to convert a UTC time to the timezone +2:

postgres=# SELECT ((timestamp '2018-05-05 10:00:00+0') AT TIME ZONE '+2');
        timezone
------------------------
 2018-05-05 12:00:00+00

typeorm gives you all the freedom to write custom field selectors or even entirely custom queries.

Another option would be - as you already mentioned - a small middleware between typeorm and your data-fetching logic to automatically translate timestamps. With moment-timezone (yes, it works on the server as well) it would look something like this:

moment.tz('2018-05-05T10:00:00.000Z', 'Europe/Vienna').format() 
// result: "2018-05-05T12:00:00+02:00"

Finally, I’d like to stress the point that using UTC at data transport and converting to local times on the client is the preferred way in most cases.

[Kannas24]

Can someone help me with #6059