The same time in time zones in the browser - in the reservation system

Question

I am looking for the best practice / solution for booking a service internationally, using the same time in any browser. I do not quite understand the logic (and dug here too).

Use case

• a user in a Brussels reservation allows talking about a haircut service based in Singapore - he flies there in a week. He selects 14:00 in the time control mode in the browser. However, the browser is set to +1 UTC.
• The SG haircut should see the time on its agenda as the time at 14:00 SG.
• the owner of a hairdresser shop travels around Dubai and he wants to see his agenda in the SG time zone, despite the fact that his browser is temporarily set to +4 UTC.

In principle, all the roles should be seen by the local time “hairdresser” regardless of what TZ they are in, and report to the server in the “store”.

Server time is UTC, timestamps are in seconds. "Shop" TZ is famous.

The problem is that I use a couple of jquery plugins (datetimepicker and calendar) that use the local time of the browser inside, and there are several thousand lines of code for analysis and correction, which makes it less convenient - the browser is in (Bruxelles | any other TZ ) for each new date () will get the local browser time. There are also rather bottlenecks (since these imaginary “hairdressing salons” are located all over the world and are selected from the map, so the target TZ is dynamic).

What is the common practice for this?

Is it easier

• mock a "dynamic" base date in js that doesn't care about the timezone, and feed with plugins
• convert server data to local TZ when loading to client
• apply another solution

Thank you very much

PS I read the best practices - but, as I said, I’m kind of obligated to use certain plugins.

Decision

I realized that I do not need the relative values ​​of these dates, since I never need to compare books of different "hairdressing salons" with time (having lat / lng for each "store", I can still recalculate the relative times, if necessary) .

Basically I only need absolute UTC values, regardless of time zone, in which case the unix time (seconds since 1970 UTC) is perfect.

Instead of adjusting the time using the offset of the user's browser on the client, sending it to the backend and fixing it there using the target offset, now I start the whole system on clear UTC dates both on the client side and on the server side / is stored and displayed for all roles, only with the exception of date and time filters, which are tied to the clock of the local browser and are not saved anywhere.

Answer 1

There are several ways to do this.

Option 1

• Forget about UTC, the time zone of the browser, and the target time zone. Just treat them like uncertain dates.
• Between the server and the client, do not transmit whole ticks or seconds - they are tied to UTC. Instead, pass local dates as ISO8601 strings without an offset or "Z".

• Use moment.js to parse and format strings without introducing a browser offset. For instance:

  // to get a Date value suitable for use with an existing control or script. var date = moment('2013-04-19T14:00').toDate(); // to get a string back from a Date that ready to go to your server. var str = moment(date).format('YYYY-MM-DDTHH:mm'); 

• On the server side, it depends on which platform you are on. ISO8601 may already be supported. For example, in .Net it's just .ToString("o") . If you need specific advice on this, let us know about your server platform / language.

Option 2

• Transfer UTC time to / from your server using ISO8601 with its qualifier "Z".
• Whenever you work with a date, use the TZDB javascript library, such as one of the ones I listed here . Convert to / from UTC and target time zone - ignore browser time zone.
• This will work fine, and now you are talking about a specific point, not some kind of indefinite local time. However, these libraries require a lot of data, and this is probably too large for such a simple task. I do not recommend this if you do not have many other conversions, such as converting the appointment time to other time zones.