Is this a zone the runtime knows? Shape first (IANA_ZONE_REGEX),
then the tz database via Intl — the same two checks the API applies, so
a picker that validates with this never sends an id the server refuses.
A type guard, so an unknown from a form or a query string narrows to a
string in one step.
Is this a zone the runtime knows? Shape first (IANA_ZONE_REGEX), then the tz database via
Intl— the same two checks the API applies, so a picker that validates with this never sends an id the server refuses.A type guard, so an
unknownfrom a form or a query string narrows to a string in one step.