How to get list of all timezones in javascript

I am developing an application with react/redux, and I started using library react-intl for formatting messages and dates.

I have already been able to show in a <FormattedDate> tag what timezone it's using.

I would like to have in a select all the possible timezones existing, so when the user picks one timezone, the <FormattedDate> changes to that format automatically.

I don't find how to list all posible timezones with react-intl.

I have also searched in google, and I did not find any built-in javascript function that does that.

Is it that way? How can I obtain that list?

Note: Don't think its the same question, since I don't want to use external libraries, if possible, if its the only solution then I will have to handle that way... :/

I recently created an array containing all timezones and found that a couple of official timezones were missing from Chromium 71.0.3578.98.

You can see that array in this comment of the bug I reported. For convenience, I've included the array below:

var aryIannaTimeZones = [
  'Europe/Andorra',
  'Asia/Dubai',
  'Asia/Kabul',
  'Europe/Tirane',
  'Asia/Yerevan',
  'Antarctica/Casey',
  'Antarctica/Davis',
  'Antarctica/DumontDUrville', // https://bugs.chromium.org/p/chromium/issues/detail?id=928068
  'Antarctica/Mawson',
  'Antarctica/Palmer',
  'Antarctica/Rothera',
  'Antarctica/Syowa',
  'Antarctica/Troll',
  'Antarctica/Vostok',
  'America/Argentina/Buenos_Aires',
  'America/Argentina/Cordoba',
  'America/Argentina/Salta',
  'America/Argentina/Jujuy',
  'America/Argentina/Tucuman',
  'America/Argentina/Catamarca',
  'America/Argentina/La_Rioja',
  'America/Argentina/San_Juan',
  'America/Argentina/Mendoza',
  'America/Argentina/San_Luis',
  'America/Argentina/Rio_Gallegos',
  'America/Argentina/Ushuaia',
  'Pacific/Pago_Pago',
  'Europe/Vienna',
  'Australia/Lord_Howe',
  'Antarctica/Macquarie',
  'Australia/Hobart',
  'Australia/Currie',
  'Australia/Melbourne',
  'Australia/Sydney',
  'Australia/Broken_Hill',
  'Australia/Brisbane',
  'Australia/Lindeman',
  'Australia/Adelaide',
  'Australia/Darwin',
  'Australia/Perth',
  'Australia/Eucla',
  'Asia/Baku',
  'America/Barbados',
  'Asia/Dhaka',
  'Europe/Brussels',
  'Europe/Sofia',
  'Atlantic/Bermuda',
  'Asia/Brunei',
  'America/La_Paz',
  'America/Noronha',
  'America/Belem',
  'America/Fortaleza',
  'America/Recife',
  'America/Araguaina',
  'America/Maceio',
  'America/Bahia',
  'America/Sao_Paulo',
  'America/Campo_Grande',
  'America/Cuiaba',
  'America/Santarem',
  'America/Porto_Velho',
  'America/Boa_Vista',
  'America/Manaus',
  'America/Eirunepe',
  'America/Rio_Branco',
  'America/Nassau',
  'Asia/Thimphu',
  'Europe/Minsk',
  'America/Belize',
  'America/St_Johns',
  'America/Halifax',
  'America/Glace_Bay',
  'America/Moncton',
  'America/Goose_Bay',
  'America/Blanc-Sablon',
  'America/Toronto',
  'America/Nipigon',
  'America/Thunder_Bay',
  'America/Iqaluit',
  'America/Pangnirtung',
  'America/Atikokan',
  'America/Winnipeg',
  'America/Rainy_River',
  'America/Resolute',
  'America/Rankin_Inlet',
  'America/Regina',
  'America/Swift_Current',
  'America/Edmonton',
  'America/Cambridge_Bay',
  'America/Yellowknife',
  'America/Inuvik',
  'America/Creston',
  'America/Dawson_Creek',
  'America/Fort_Nelson',
  'America/Vancouver',
  'America/Whitehorse',
  'America/Dawson',
  'Indian/Cocos',
  'Europe/Zurich',
  'Africa/Abidjan',
  'Pacific/Rarotonga',
  'America/Santiago',
  'America/Punta_Arenas',
  'Pacific/Easter',
  'Asia/Shanghai',
  'Asia/Urumqi',
  'America/Bogota',
  'America/Costa_Rica',
  'America/Havana',
  'Atlantic/Cape_Verde',
  'America/Curacao',
  'Indian/Christmas',
  'Asia/Nicosia',
  'Asia/Famagusta',
  'Europe/Prague',
  'Europe/Berlin',
  'Europe/Copenhagen',
  'America/Santo_Domingo',
  'Africa/Algiers',
  'America/Guayaquil',
  'Pacific/Galapagos',
  'Europe/Tallinn',
  'Africa/Cairo',
  'Africa/El_Aaiun',
  'Europe/Madrid',
  'Africa/Ceuta',
  'Atlantic/Canary',
  'Europe/Helsinki',
  'Pacific/Fiji',
  'Atlantic/Stanley',
  'Pacific/Chuuk',
  'Pacific/Pohnpei',
  'Pacific/Kosrae',
  'Atlantic/Faroe',
  'Europe/Paris',
  'Europe/London',
  'Asia/Tbilisi',
  'America/Cayenne',
  'Africa/Accra',
  'Europe/Gibraltar',
  'America/Godthab',
  'America/Danmarkshavn',
  'America/Scoresbysund',
  'America/Thule',
  'Europe/Athens',
  'Atlantic/South_Georgia',
  'America/Guatemala',
  'Pacific/Guam',
  'Africa/Bissau',
  'America/Guyana',
  'Asia/Hong_Kong',
  'America/Tegucigalpa',
  'America/Port-au-Prince',
  'Europe/Budapest',
  'Asia/Jakarta',
  'Asia/Pontianak',
  'Asia/Makassar',
  'Asia/Jayapura',
  'Europe/Dublin',
  'Asia/Jerusalem',
  'Asia/Kolkata',
  'Indian/Chagos',
  'Asia/Baghdad',
  'Asia/Tehran',
  'Atlantic/Reykjavik',
  'Europe/Rome',
  'America/Jamaica',
  'Asia/Amman',
  'Asia/Tokyo',
  'Africa/Nairobi',
  'Asia/Bishkek',
  'Pacific/Tarawa',
  'Pacific/Enderbury',
  'Pacific/Kiritimati',
  'Asia/Pyongyang',
  'Asia/Seoul',
  'Asia/Almaty',
  'Asia/Qyzylorda',
  'Asia/Qostanay', // https://bugs.chromium.org/p/chromium/issues/detail?id=928068
  'Asia/Aqtobe',
  'Asia/Aqtau',
  'Asia/Atyrau',
  'Asia/Oral',
  'Asia/Beirut',
  'Asia/Colombo',
  'Africa/Monrovia',
  'Europe/Vilnius',
  'Europe/Luxembourg',
  'Europe/Riga',
  'Africa/Tripoli',
  'Africa/Casablanca',
  'Europe/Monaco',
  'Europe/Chisinau',
  'Pacific/Majuro',
  'Pacific/Kwajalein',
  'Asia/Yangon',
  'Asia/Ulaanbaatar',
  'Asia/Hovd',
  'Asia/Choibalsan',
  'Asia/Macau',
  'America/Martinique',
  'Europe/Malta',
  'Indian/Mauritius',
  'Indian/Maldives',
  'America/Mexico_City',
  'America/Cancun',
  'America/Merida',
  'America/Monterrey',
  'America/Matamoros',
  'America/Mazatlan',
  'America/Chihuahua',
  'America/Ojinaga',
  'America/Hermosillo',
  'America/Tijuana',
  'America/Bahia_Banderas',
  'Asia/Kuala_Lumpur',
  'Asia/Kuching',
  'Africa/Maputo',
  'Africa/Windhoek',
  'Pacific/Noumea',
  'Pacific/Norfolk',
  'Africa/Lagos',
  'America/Managua',
  'Europe/Amsterdam',
  'Europe/Oslo',
  'Asia/Kathmandu',
  'Pacific/Nauru',
  'Pacific/Niue',
  'Pacific/Auckland',
  'Pacific/Chatham',
  'America/Panama',
  'America/Lima',
  'Pacific/Tahiti',
  'Pacific/Marquesas',
  'Pacific/Gambier',
  'Pacific/Port_Moresby',
  'Pacific/Bougainville',
  'Asia/Manila',
  'Asia/Karachi',
  'Europe/Warsaw',
  'America/Miquelon',
  'Pacific/Pitcairn',
  'America/Puerto_Rico',
  'Asia/Gaza',
  'Asia/Hebron',
  'Europe/Lisbon',
  'Atlantic/Madeira',
  'Atlantic/Azores',
  'Pacific/Palau',
  'America/Asuncion',
  'Asia/Qatar',
  'Indian/Reunion',
  'Europe/Bucharest',
  'Europe/Belgrade',
  'Europe/Kaliningrad',
  'Europe/Moscow',
  'Europe/Simferopol',
  'Europe/Kirov',
  'Europe/Astrakhan',
  'Europe/Volgograd',
  'Europe/Saratov',
  'Europe/Ulyanovsk',
  'Europe/Samara',
  'Asia/Yekaterinburg',
  'Asia/Omsk',
  'Asia/Novosibirsk',
  'Asia/Barnaul',
  'Asia/Tomsk',
  'Asia/Novokuznetsk',
  'Asia/Krasnoyarsk',
  'Asia/Irkutsk',
  'Asia/Chita',
  'Asia/Yakutsk',
  'Asia/Khandyga',
  'Asia/Vladivostok',
  'Asia/Ust-Nera',
  'Asia/Magadan',
  'Asia/Sakhalin',
  'Asia/Srednekolymsk',
  'Asia/Kamchatka',
  'Asia/Anadyr',
  'Asia/Riyadh',
  'Pacific/Guadalcanal',
  'Indian/Mahe',
  'Africa/Khartoum',
  'Europe/Stockholm',
  'Asia/Singapore',
  'America/Paramaribo',
  'Africa/Juba',
  'Africa/Sao_Tome',
  'America/El_Salvador',
  'Asia/Damascus',
  'America/Grand_Turk',
  'Africa/Ndjamena',
  'Indian/Kerguelen',
  'Asia/Bangkok',
  'Asia/Dushanbe',
  'Pacific/Fakaofo',
  'Asia/Dili',
  'Asia/Ashgabat',
  'Africa/Tunis',
  'Pacific/Tongatapu',
  'Europe/Istanbul',
  'America/Port_of_Spain',
  'Pacific/Funafuti',
  'Asia/Taipei',
  'Europe/Kiev',
  'Europe/Uzhgorod',
  'Europe/Zaporozhye',
  'Pacific/Wake',
  'America/New_York',
  'America/Detroit',
  'America/Kentucky/Louisville',
  'America/Kentucky/Monticello',
  'America/Indiana/Indianapolis',
  'America/Indiana/Vincennes',
  'America/Indiana/Winamac',
  'America/Indiana/Marengo',
  'America/Indiana/Petersburg',
  'America/Indiana/Vevay',
  'America/Chicago',
  'America/Indiana/Tell_City',
  'America/Indiana/Knox',
  'America/Menominee',
  'America/North_Dakota/Center',
  'America/North_Dakota/New_Salem',
  'America/North_Dakota/Beulah',
  'America/Denver',
  'America/Boise',
  'America/Phoenix',
  'America/Los_Angeles',
  'America/Anchorage',
  'America/Juneau',
  'America/Sitka',
  'America/Metlakatla',
  'America/Yakutat',
  'America/Nome',
  'America/Adak',
  'Pacific/Honolulu',
  'America/Montevideo',
  'Asia/Samarkand',
  'Asia/Tashkent',
  'America/Caracas',
  'Asia/Ho_Chi_Minh',
  'Pacific/Efate',
  'Pacific/Wallis',
  'Pacific/Apia',
  'Africa/Johannesburg'
];

let date = new Date;
aryIannaTimeZones.forEach((timeZone) => {

  let strTime = date.toLocaleString("en-US", {
    timeZone: `${timeZone}`
  });
  console.log(timeZone, strTime);
});

If you're like me, in wondering why there are so many timezones, check out this question.

For the future searchers, it's possible to get a list of all timezones using moment-timezone.

import momentTZ from 'moment-timezone';

const defaultTimeZone = momentTZ.tz.guess();
const timeZonesList = momentTZ.tz.names();

I too needed to have a complete time zone list with preformated data like:

{
  name: "America/Los_Angeles",
  alternativeName: "Pacific Time",
  group: ["America/Los_Angeles"],
  countryName: "United States",
  mainCities: ["Los Angeles", "San Diego"],
  rawOffsetInMinutes: -480, // "raw" time zone offset, when there's no DST in place
  rawFormat: "-08:00 Pacific Time - Los Angeles, San Diego",
  currentTimeOffsetInMinutes: -420, // "current" time zone offset, this is why getTimeZones() is a method and not just an object: it can only work at runtime
  currentTimeFormat: "-07:00 Pacific Time - Los Angeles, San Diego",
}

Since I could not find a good list that would also be maintained, I created an npm package for it: https://github.com/vvo/tzdb/. The list of time zones is automatically updated when there are changes (like new time zones).

You can then use https://github.com/moment/luxon if you need to manipulate dates with time zones.

The list of time zones is grouped to reduce the number of time zones. We do grouping only when: same country AND same offsets (DST, non DST).

This basically gives you a time zone list that is very close to the one from Google Calendar.

Good luck!

I did not find the list of time-zone through browser javascript so created array of timezone list and used it.

Till Dec 25, 2020 in JAVA 11 ZoneRulesProvider.java

Create array/collection and use this without external library

I found 600 sorted TimeZone

'Africa/Abidjan','Africa/Accra','Africa/Addis_Ababa','Africa/Algiers','Africa/Asmara','Africa/Asmera','Africa/Bamako','Africa/Bangui','Africa/Banjul','Africa/Bissau','Africa/Blantyre','Africa/Brazzaville','Africa/Bujumbura','Africa/Cairo','Africa/Casablanca','Africa/Ceuta','Africa/Conakry','Africa/Dakar','Africa/Dar_es_Salaam','Africa/Djibouti','Africa/Douala','Africa/El_Aaiun','Africa/Freetown','Africa/Gaborone','Africa/Harare','Africa/Johannesburg','Africa/Juba','Africa/Kampala','Africa/Khartoum','Africa/Kigali','Africa/Kinshasa','Africa/Lagos','Africa/Libreville','Africa/Lome','Africa/Luanda','Africa/Lubumbashi','Africa/Lusaka','Africa/Malabo','Africa/Maputo','Africa/Maseru','Africa/Mbabane','Africa/Mogadishu','Africa/Monrovia','Africa/Nairobi','Africa/Ndjamena','Africa/Niamey','Africa/Nouakchott','Africa/Ouagadougou','Africa/Porto-Novo','Africa/Sao_Tome','Africa/Timbuktu','Africa/Tripoli','Africa/Tunis','Africa/Windhoek','America/Adak','America/Anchorage','America/Anguilla','America/Antigua','America/Araguaina','America/Argentina/Buenos_Aires','America/Argentina/Catamarca','America/Argentina/ComodRivadavia','America/Argentina/Cordoba','America/Argentina/Jujuy','America/Argentina/La_Rioja','America/Argentina/Mendoza','America/Argentina/Rio_Gallegos','America/Argentina/Salta','America/Argentina/San_Juan','America/Argentina/San_Luis','America/Argentina/Tucuman','America/Argentina/Ushuaia','America/Aruba','America/Asuncion','America/Atikokan','America/Atka','America/Bahia','America/Bahia_Banderas','America/Barbados','America/Belem','America/Belize','America/Blanc-Sablon','America/Boa_Vista','America/Bogota','America/Boise','America/Buenos_Aires','America/Cambridge_Bay','America/Campo_Grande','America/Cancun','America/Caracas','America/Catamarca','America/Cayenne','America/Cayman','America/Chicago','America/Chihuahua','America/Coral_Harbour','America/Cordoba','America/Costa_Rica','America/Creston','America/Cuiaba','America/Curacao','America/Danmarkshavn','America/Dawson','America/Dawson_Creek','America/Denver','America/Detroit','America/Dominica','America/Edmonton','America/Eirunepe','America/El_Salvador','America/Ensenada','America/Fort_Nelson','America/Fort_Wayne','America/Fortaleza','America/Glace_Bay','America/Godthab','America/Goose_Bay','America/Grand_Turk','America/Grenada','America/Guadeloupe','America/Guatemala','America/Guayaquil','America/Guyana','America/Halifax','America/Havana','America/Hermosillo','America/Indiana/Indianapolis','America/Indiana/Knox','America/Indiana/Marengo','America/Indiana/Petersburg','America/Indiana/Tell_City','America/Indiana/Vevay','America/Indiana/Vincennes','America/Indiana/Winamac','America/Indianapolis','America/Inuvik','America/Iqaluit','America/Jamaica','America/Jujuy','America/Juneau','America/Kentucky/Louisville','America/Kentucky/Monticello','America/Knox_IN','America/Kralendijk','America/La_Paz','America/Lima','America/Los_Angeles','America/Louisville','America/Lower_Princes','America/Maceio','America/Managua','America/Manaus','America/Marigot','America/Martinique','America/Matamoros','America/Mazatlan','America/Mendoza','America/Menominee','America/Merida','America/Metlakatla','America/Mexico_City','America/Miquelon','America/Moncton','America/Monterrey','America/Montevideo','America/Montreal','America/Montserrat','America/Nassau','America/New_York','America/Nipigon','America/Nome','America/Noronha','America/North_Dakota/Beulah','America/North_Dakota/Center','America/North_Dakota/New_Salem','America/Ojinaga','America/Panama','America/Pangnirtung','America/Paramaribo','America/Phoenix','America/Port-au-Prince','America/Port_of_Spain','America/Porto_Acre','America/Porto_Velho','America/Puerto_Rico','America/Punta_Arenas','America/Rainy_River','America/Rankin_Inlet','America/Recife','America/Regina','America/Resolute','America/Rio_Branco','America/Rosario','America/Santa_Isabel','America/Santarem','America/Santiago','America/Santo_Domingo','America/Sao_Paulo','America/Scoresbysund','America/Shiprock','America/Sitka','America/St_Barthelemy','America/St_Johns','America/St_Kitts','America/St_Lucia','America/St_Thomas','America/St_Vincent','America/Swift_Current','America/Tegucigalpa','America/Thule','America/Thunder_Bay','America/Tijuana','America/Toronto','America/Tortola','America/Vancouver','America/Virgin','America/Whitehorse','America/Winnipeg','America/Yakutat','America/Yellowknife','Antarctica/Casey','Antarctica/Davis','Antarctica/DumontDUrville','Antarctica/Macquarie','Antarctica/Mawson','Antarctica/McMurdo','Antarctica/Palmer','Antarctica/Rothera','Antarctica/South_Pole','Antarctica/Syowa','Antarctica/Troll','Antarctica/Vostok','Arctic/Longyearbyen','Asia/Aden','Asia/Almaty','Asia/Amman','Asia/Anadyr','Asia/Aqtau','Asia/Aqtobe','Asia/Ashgabat','Asia/Ashkhabad','Asia/Atyrau','Asia/Baghdad','Asia/Bahrain','Asia/Baku','Asia/Bangkok','Asia/Barnaul','Asia/Beirut','Asia/Bishkek','Asia/Brunei','Asia/Calcutta','Asia/Chita','Asia/Choibalsan','Asia/Chongqing','Asia/Chungking','Asia/Colombo','Asia/Dacca','Asia/Damascus','Asia/Dhaka','Asia/Dili','Asia/Dubai','Asia/Dushanbe','Asia/Famagusta','Asia/Gaza','Asia/Harbin','Asia/Hebron','Asia/Ho_Chi_Minh','Asia/Hong_Kong','Asia/Hovd','Asia/Irkutsk','Asia/Istanbul','Asia/Jakarta','Asia/Jayapura','Asia/Jerusalem','Asia/Kabul','Asia/Kamchatka','Asia/Karachi','Asia/Kashgar','Asia/Kathmandu','Asia/Katmandu','Asia/Khandyga','Asia/Kolkata','Asia/Krasnoyarsk','Asia/Kuala_Lumpur','Asia/Kuching','Asia/Kuwait','Asia/Macao','Asia/Macau','Asia/Magadan','Asia/Makassar','Asia/Manila','Asia/Muscat','Asia/Nicosia','Asia/Novokuznetsk','Asia/Novosibirsk','Asia/Omsk','Asia/Oral','Asia/Phnom_Penh','Asia/Pontianak','Asia/Pyongyang','Asia/Qatar','Asia/Qostanay','Asia/Qyzylorda','Asia/Rangoon','Asia/Riyadh','Asia/Saigon','Asia/Sakhalin','Asia/Samarkand','Asia/Seoul','Asia/Shanghai','Asia/Singapore','Asia/Srednekolymsk','Asia/Taipei','Asia/Tashkent','Asia/Tbilisi','Asia/Tehran','Asia/Tel_Aviv','Asia/Thimbu','Asia/Thimphu','Asia/Tokyo','Asia/Tomsk','Asia/Ujung_Pandang','Asia/Ulaanbaatar','Asia/Ulan_Bator','Asia/Urumqi','Asia/Ust-Nera','Asia/Vientiane','Asia/Vladivostok','Asia/Yakutsk','Asia/Yangon','Asia/Yekaterinburg','Asia/Yerevan','Atlantic/Azores','Atlantic/Bermuda','Atlantic/Canary','Atlantic/Cape_Verde','Atlantic/Faeroe','Atlantic/Faroe','Atlantic/Jan_Mayen','Atlantic/Madeira','Atlantic/Reykjavik','Atlantic/South_Georgia','Atlantic/St_Helena','Atlantic/Stanley','Australia/ACT','Australia/Adelaide','Australia/Brisbane','Australia/Broken_Hill','Australia/Canberra','Australia/Currie','Australia/Darwin','Australia/Eucla','Australia/Hobart','Australia/LHI','Australia/Lindeman','Australia/Lord_Howe','Australia/Melbourne','Australia/NSW','Australia/North','Australia/Perth','Australia/Queensland','Australia/South','Australia/Sydney','Australia/Tasmania','Australia/Victoria','Australia/West','Australia/Yancowinna','Brazil/Acre','Brazil/DeNoronha','Brazil/East','Brazil/West','CET','CST6CDT','Canada/Atlantic','Canada/Central','Canada/Eastern','Canada/Mountain','Canada/Newfoundland','Canada/Pacific','Canada/Saskatchewan','Canada/Yukon','Chile/Continental','Chile/EasterIsland','Cuba','EET','EST5EDT','Egypt','Eire','Etc/GMT','Etc/GMT+0','Etc/GMT+1','Etc/GMT+10','Etc/GMT+11','Etc/GMT+12','Etc/GMT+2','Etc/GMT+3','Etc/GMT+4','Etc/GMT+5','Etc/GMT+6','Etc/GMT+7','Etc/GMT+8','Etc/GMT+9','Etc/GMT-0','Etc/GMT-1','Etc/GMT-10','Etc/GMT-11','Etc/GMT-12','Etc/GMT-13','Etc/GMT-14','Etc/GMT-2','Etc/GMT-3','Etc/GMT-4','Etc/GMT-5','Etc/GMT-6','Etc/GMT-7','Etc/GMT-8','Etc/GMT-9','Etc/GMT0','Etc/Greenwich','Etc/UCT','Etc/UTC','Etc/Universal','Etc/Zulu','Europe/Amsterdam','Europe/Andorra','Europe/Astrakhan','Europe/Athens','Europe/Belfast','Europe/Belgrade','Europe/Berlin','Europe/Bratislava','Europe/Brussels','Europe/Bucharest','Europe/Budapest','Europe/Busingen','Europe/Chisinau','Europe/Copenhagen','Europe/Dublin','Europe/Gibraltar','Europe/Guernsey','Europe/Helsinki','Europe/Isle_of_Man','Europe/Istanbul','Europe/Jersey','Europe/Kaliningrad','Europe/Kiev','Europe/Kirov','Europe/Lisbon','Europe/Ljubljana','Europe/London','Europe/Luxembourg','Europe/Madrid','Europe/Malta','Europe/Mariehamn','Europe/Minsk','Europe/Monaco','Europe/Moscow','Europe/Nicosia','Europe/Oslo','Europe/Paris','Europe/Podgorica','Europe/Prague','Europe/Riga','Europe/Rome','Europe/Samara','Europe/San_Marino','Europe/Sarajevo','Europe/Saratov','Europe/Simferopol','Europe/Skopje','Europe/Sofia','Europe/Stockholm','Europe/Tallinn','Europe/Tirane','Europe/Tiraspol','Europe/Ulyanovsk','Europe/Uzhgorod','Europe/Vaduz','Europe/Vatican','Europe/Vienna','Europe/Vilnius','Europe/Volgograd','Europe/Warsaw','Europe/Zagreb','Europe/Zaporozhye','Europe/Zurich','GB','GB-Eire','GMT','GMT0','Greenwich','Hongkong','Iceland','Indian/Antananarivo','Indian/Chagos','Indian/Christmas','Indian/Cocos','Indian/Comoro','Indian/Kerguelen','Indian/Mahe','Indian/Maldives','Indian/Mauritius','Indian/Mayotte','Indian/Reunion','Iran','Israel','Jamaica','Japan','Kwajalein','Libya','MET','MST7MDT','Mexico/BajaNorte','Mexico/BajaSur','Mexico/General','NZ','NZ-CHAT','Navajo','PRC','PST8PDT','Pacific/Apia','Pacific/Auckland','Pacific/Bougainville','Pacific/Chatham','Pacific/Chuuk','Pacific/Easter','Pacific/Efate','Pacific/Enderbury','Pacific/Fakaofo','Pacific/Fiji','Pacific/Funafuti','Pacific/Galapagos','Pacific/Gambier','Pacific/Guadalcanal','Pacific/Guam','Pacific/Honolulu','Pacific/Johnston','Pacific/Kiritimati','Pacific/Kosrae','Pacific/Kwajalein','Pacific/Majuro','Pacific/Marquesas','Pacific/Midway','Pacific/Nauru','Pacific/Niue','Pacific/Norfolk','Pacific/Noumea','Pacific/Pago_Pago','Pacific/Palau','Pacific/Pitcairn','Pacific/Pohnpei','Pacific/Ponape','Pacific/Port_Moresby','Pacific/Rarotonga','Pacific/Saipan','Pacific/Samoa','Pacific/Tahiti','Pacific/Tarawa','Pacific/Tongatapu','Pacific/Truk','Pacific/Wake','Pacific/Wallis','Pacific/Yap','Poland','Portugal','ROK','Singapore','SystemV/AST4','SystemV/AST4ADT','SystemV/CST6','SystemV/CST6CDT','SystemV/EST5','SystemV/EST5EDT','SystemV/HST10','SystemV/MST7','SystemV/MST7MDT','SystemV/PST8','SystemV/PST8PDT','SystemV/YST9','SystemV/YST9YDT','Turkey','UCT','US/Alaska','US/Aleutian','US/Arizona','US/Central','US/East-Indiana','US/Eastern','US/Hawaii','US/Indiana-Starke','US/Michigan','US/Mountain','US/Pacific','US/Pacific-New','US/Samoa','UTC','Universal','W-SU','WET','Zulu' 

The react-intl library's time zone functionality is provided exclusively by the ECMAScript Internationalization API features that are integrated into the browser.

While IANA time zone support is part of this spec, it currently only covers two scenarios:

• Formating a Date object to a string, converting to a specific time zone in the process.

• Determining the user's local time zone identifier.

Unfortunately, there is no function defined by the spec for enumerating the list of available time zones.

Additionally, note that support for the two functions it does have is currently limited to a handful of browsers. It will likely be quite some time before these capabilities can be depended upon. The ECMAScript Compatibility Table shows which browsers are supported. Under DateTimeFormat you'll find "resolvedOptions().timeZone defaults to the host environment" and "accepts IANA timezone names" that track these features.