Is there a way to check if timezone name valid or not in JavaScript without using external library?
When user enters timezone name in text field I want to verify whether zone is valid or not?
I know we can do it easily using moment-timezone library. But I don’t want to use any extra library. I’m looking for pure JavaScript way.
isValidTimeZone(name) { //return true/false } isValidTimeZone('Asia/Colombo'); //returns true isValidTimeZone('America/Los_Angeles'); //returns true isValidTimeZone('MyTimeZone/ME'); //returns false
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Answer
In environments that fully support IANA time zone identifiers in ECMA-402 (ECMAScript Internationalization API), you can try using a time zone in a DateTimeFormat
(or in the options of to toLocaleString
) and it will throw an exception if it is not a valid time zone. You can use this to test for validity, but only in environments where it is supported.
function isValidTimeZone(tz) { if (!Intl || !Intl.DateTimeFormat().resolvedOptions().timeZone) { throw new Error('Time zones are not available in this environment'); } try { Intl.DateTimeFormat(undefined, {timeZone: tz}); return true; } catch (ex) { return false; } } // Usage: isValidTimeZone('America/Los_Angeles') // true isValidTimeZone('Foo/Bar') // false
If you cannot be assured of your environment, then the best way would be with moment-timezone
!!moment.tz.zone('America/Los_Angeles') // true !!moment.tz.zone('Foo/Bar') // false
Of course, you could always extract your own array of time zone names (perhaps with moment.tz.names()
and test against that.