getTimezoneOffset

getTimezoneOffset is a tiny library ( less than 1k ) for getting timezone offsets.

It returns the timezone offset in minutes for any IANA timezone name for any valid javascript date in the past, present and future.

Example

var now = new Date();

var offset = getTimezoneOffset( 'America/New_York', now );

console.log( `Timezone offset in New York is ${offset}` );

How it works

getTimezoneOffset is tiny because it ships without a database of timezones, using the tz database of the underlying operating system via the global Intl object.

Internationalization is a relatively new feature for javascript engines; Engine support is tracked here , but boils down to;

• Node: 4+
• IE/Edge: Edge only
• FF: 52+
• Chromium: 45+
• Safari: 10+

Tests

The tests will validate the library functionality and the javascript engine's implementation of Intl.DateTimeFormat.

To test in node

npm test

To test in a browser

npm run test:browser

Then open test.html in a browser and view the console output.