Javascript Set Timezone Offset and time settings on Client

[Isiah Meadows]

I'd personally prefer this to be settable on the instance, rather than
the global object - you can manage universal dates more easily across
time zones this way, and it still enables developers to have the
fallback in case they need an escape or if they have code that relies
on time zones remaining static as long as they have it and control
creation. (The current `Date.UTC` stuff is not very helpful for
anything not so simple you barely even need it.)

I'm not on the TC39 committee, so I can't really vote on this or
anything, though.

-----

Isiah Meadows
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On Sun, Apr 29, 2018 at 12:49 PM, Iman Mohamadi
<iman.mohamadi.dev at gmail.com> wrote:
> To clear things out, I don't mean any changes to the actual Date time of
> Javascript. What I want to discuss about is a problem with a very simple
> solution.
>
> Issue: Since Javascript code is mainly executed on a device that you might
> not have access to  timezone and time settings that would be very help full
> to provide a way to adjust timezone and time settings that are taken from OS
> via Javascript code. Since now if you set your OS timezone setting to
> "Tehran" you will get -270 when you write this code in your browser console:
>
> ```
> (new Date()).getTimezoneOffset();
>>> -270
> ```
>
> This is cool but what If I know I want to use another timezone? With current
> implementation I should mess around with date objects and do hacks and
> tricks but a very easy way would be to allow me to override OS preferences.
> That would be like so:
>
> ```
> Date.setClientTimezoneOffset(300)    //Chicago timezone
> (new Date()).getTimezoneOffset();
>>> 300
> ```
> Now I don't need to worry about myDate.getHours(), and minutes and seconds.
> Right now Javascript keeps this timezone offset to itself and leave me in
> pain of dealing with all incoming issues. However a simple set method could
> save a lot of time. This is the same with time settings. My browser takes
> time settings form my OS, if my OS time is 10:30 and I do this:
>
> ```
> var myDate = new Date();
> console.log(myDate.getHours());
>>> 10
> console.log(myDate.getMinutes());
>>> 30
> ```
> But what if correct time is 12:00 ? This can be annoying to fix how ever It
> could be handled in browser like this:
>
> ```
> Date.setClientHours(12, 0, 0);
> var myDate = new Date();
> console.log(myDate.getHours());
>>> 12
> console.log(myDate.getMinutes());
>>> 0
> ```
>
> This can be implemented by keeping 12:00 - 10:30 = 1:30h which is OS to
> developer preference difference and use this offset to create correct
> Date.now(). If user changes it's time settings it can be set back to OS
> preferences.
>
> What do you thing about the main idea?
>
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