Fetches the zone.tab file from https://data.iana.org/time-zones/tzdb/zone.tab and returns a promise with a formatted timezone object.
$ npm install zonetab
$ zonetab -f > zonetab.json
const getZonetab = require('zonetab')
getZonetab().then(zonetabMap => {
// zonetabMap output:
// {
// ...
// "Europe/Copenhagen": {
// "code": "DK",
// "coordinates": "+5540+01235",
// "comments": null,
// },
// ...
// }
})