@burglekitt/gmt
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Temporal-based date and time utilities with timezone support and polyfill integration
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TypeScript
/**
* Return an IANA timeZone's UTC offset at a given instant.
*
* - Unlike `getZonedOffset`, this doesn't need an existing zoned value in
* hand — pass any timeZone identifier and an instant to look up, which is
* why (like `getDstTransitions`) it lives in `get/` despite taking two
* arguments: neither is a date *value* being described, both are
* coordinates for a zone-level lookup.
* - Returns "" for an invalid timeZone or instant.
*
* @param timeZone IANA timeZone identifier
* @param instant ISO 8601 instant string (e.g. "2024-07-15T12:00:00Z")
* @returns offset string (e.g. "-04:00"), or "" on invalid input
*
* @example getTimeZoneOffset("America/New_York", "2024-07-15T12:00:00Z") // "-04:00"
* @example getTimeZoneOffset("America/New_York", "2024-01-15T12:00:00Z") // "-05:00"
* @example getTimeZoneOffset("Asia/Kathmandu", "2024-01-15T12:00:00Z") // "+05:45"
* @example getTimeZoneOffset("Invalid/Zone", "2024-07-15T12:00:00Z") // ""
* @example getTimeZoneOffset("America/New_York", "not an instant") // ""
*/
export declare function getTimeZoneOffset(timeZone: string, instant: string): string;