CODEWITHSUNDEEP
javascriptdatetimetimezone
ND_Coder
ND_Coder

Reputation: 157

Time in Known Location with Known Offset and NO Daylight Saving Time

With the hundreds of posts concerning Javascript time questions, I'm certain this has been addressed but I've been through a couple of dozen posts so far and none answer my specific question. I know the offset (-7) and in this particular State in the USA (Arizona) there is NO DST. I just want to display the time in Arizona to any user. All the posts I've reviewed seem to imply that I need to use

return new Date().getTimezoneOffset();

from the local computer as part of my calculations but I'm not sure why that would be necessary? Would this be a viable solution?

const now = new Date();
        return {
            hour: (now.getUTCHours() -7)
            minute: now.getMinutes(),
        };

Upvotes: 3

Views: 138

Answers (3)

RobG
RobG

Reputation: 147373

You can use the Intl object and Etc pseudo–timezone for a fixed offset. The EMCAScript version only supports whole hour offsets and the sign is the reverse of convention.

E.g.

console.log('Current time in UTC-7: ' +
  new Date().toLocaleString('default',{timeZone:'Etc/GMT+7', hour:'numeric', minute:'2-digit'})
);

console.log('Current time in UTC-7: ' +
  new Date().toLocaleTimeString('default',{timeZone:'Etc/GMT+7'})
);

Upvotes: 1

Matt Johnson-Pint
Matt Johnson-Pint

Reputation: 241515

There is no DST in Arizona presently, but that doesn't mean there never will be. Sure, unlikely - but not impossible.

A more robust solution, which also accounts for locale formatting preferences of the user, is as follows:

const s = new Date().toLocaleTimeString(undefined, {
  timeZone: 'America/Phoenix'
});
console.log(s);

This will work with any IANA time zone identifier, accounting for DST when applicable, or not - depending on the time zone.

If you want the exact output as in your question, try something like this:

const s = new Date().toLocaleString('en', {
  timeZone: 'America/Phoenix',
  hour12: false,
  hour: 'numeric',
  minute: 'numeric'
});
const p = s.split(':');
const o = {
  hour: parseInt(p[0]),
  minute: parseInt(p[1])
};
console.log(o);

Upvotes: 3

Lajos Arpad
Lajos Arpad

Reputation: 76454

You do not need to getTimezoneOffset, but you will need to handle the case when the hours are smaller than 7:

const now = new Date();
        console.log( {
            hour: ((now.getUTCHours() -7) % 24),
            minute: now.getMinutes(),
        });

Upvotes: 1

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