Since November 2018 Evan Siroky's geo-tz supports preCache method. Therefore, this package is no longer maintained.

Timezone lookup service.

This is modified version of Evan Siroky's amazing geo-tz, but optimized for speed without any compromises.

The approach here is brutally simple: Load everything into memory. Doing so, fast-timezone will typically consume around 900MB memory extra. Don't even think about using it if you can't spare at least 1GB of extra memory per process.

npm i fast-timezone

const getTimezone = require('fast-timezone');
// It is a good idea to wait until the data is loaded. If any lookups are
// performed before that, an error will be thrown.
await getTimezone.loaded;
// Get a time zone by location:
const zone = getTimezone(50.047, 14.435);

Optionally, you can supply a timestamp as the third argument, and you will get the time zone at that time.

In case a time zone is found (which is the case if the arguments are valid), an object is returned:

{
 "id": "Europe/Prague",
 "name": "CEST",
 "offset": 120,
 "designator": "+02:00",
 "type": "t"
}

For a nautical time zone the result looks like:

{
 "id": "Etc/GMT+3",
 "name": "-03",
 "offset": -180,
 "designator": "-03:00",
 "type": "n"
}

where offset is the offset in minutes at the moment of the query, and designator is the zone designator according to ISO 8601.

Also note, the type is n for nautical time zones.

This software is licenced under the MIT license.