@vvo/tzdb
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Always up to date list of time zones, with grouping and major cities
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This is a list and npm package of:
- "simplified" [IANA time zones](https://www.iana.org/time-zones) with their alternative names like `Pacific Time` instead of `America/Los_Angeles`, along with major cities for each time zone.
- all existing raw IANA time zones names
- "raw" offsets along with current time offsets
- also includes [deprecated time zone names](https://data.iana.org/time-zones/data/backward) for compatibility
The data and npm packages are **automatically updated** whenever there are changes to https://www.geonames.org/ which is generated from IANA databases.
This is useful whenever you want to build a time zone select menu in your application.
Installation:
```bash
npm add @vvo/tzdb
```
Usage:
```js
import { getTimeZones, rawTimeZones, timeZonesNames, abbreviations } from "@vvo/tzdb";
```
```js
const timeZones = getTimeZones();
// You can also provide an optional parameter to include UTC in the result.
// This adds a time zone with the name "UTC" and a fixed offset of 0.
const timeZonesWithUtc = getTimeZones({ includeUtc: true });
```
This method returns an array of time zones objects:
```js
[
// ...
{
name: "America/Los_Angeles",
alternativeName: "Pacific Time",
group: ["America/Los_Angeles"],
continentCode: "NA",
continentName: "North America",
countryName: "United States",
countryCode: "US",
mainCities: ["Los Angeles", "San Diego", "San Jose", "San Francisco"],
rawOffsetInMinutes: -480,
abbreviation: "PST",
rawFormat: "-08:00 Pacific Time - Los Angeles, San Diego, San Jose, San Francisco",
currentTimeOffsetInMinutes: -420, // "current" time zone offset, this is why getTimeZones() is a method and not just an object: it works at runtime
currentTimeFormat: "-07:00 Pacific Time - Los Angeles, San Diego",
},
// ...
];
```
When relevant, time zones are grouped. The rules for grouping are:
- if the time zones are in the same country
- if the DST or summer time offsets are the same
- if the non-DST, non-summer time offsets are the same
- then we group the time zones
- the "main" time zone name (`name` attribute), is always the one from the most populated city
Here's a grouping example:
```js
{
name: "America/Dawson_Creek",
alternativeName: "Mountain Time",
group: ["America/Creston", "America/Dawson_Creek", "America/Fort_Nelson"],
continentCode: "NA",
continentName: "North America",
countryName: "Canada",
countryCode: "CA",
mainCities: ["Fort St. John", "Creston", "Fort Nelson"],
rawOffsetInMinutes: -420,
abbreviation: "MST",
rawFormat: "-07:00 Mountain Time - Fort St. John, Creston, Fort Nelson",
currentTimeOffsetInMinutes: -420,
currentTimeFormat: "-07:00 Mountain Time - Fort St. John, Creston"
}
```
This is an array of time zone objects without the current time information:
```js
[
// ...
{
name: "America/Los_Angeles",
alternativeName: "Pacific Time",
group: ["America/Los_Angeles"],
continentCode: "NA",
continentName: "North America",
countryName: "United States",
countryCode: "US",
mainCities: ["Los Angeles", "San Diego", "San Jose", "San Francisco"],
rawOffsetInMinutes: -480,
abbreviation: "PST",
rawFormat: "-08:00 Pacific Time - Los Angeles, San Diego, San Jose, San Francisco",
},
// ...
];
```
This is an array of time zone names:
```js
[
// ...
"America/Juneau",
"America/Kentucky/Louisville",
"America/Kentucky/Monticello",
"America/Kralendijk",
"America/La_Paz",
"America/Lima",
"America/Los_Angeles",
"America/Lower_Princes",
"America/Maceio",
"America/Managua",
"America/Manaus",
"America/Marigot",
"America/Martinique",
"America/Matamoros",
// ...
];
```
This is an object mapping timezone abbreviations to their full forms:
```js
{
// ...
"Australian Central Daylight Time": "ACDT",
"Australian Central Standard Time": "ACST",
"Australian Central Time": "ACT",
"Australian Central Western Standard Time": "ACWST",
"Australian Eastern Daylight Time": "AEDT",
"Australian Eastern Standard Time": "AEST",
"Australian Eastern Time": "AET",
"Australian Western Daylight Time": "AWDT",
"Australian Western Standard Time": "AWST",
"Azerbaijan Summer Time": "AZST",
"Azerbaijan Time": "AZT",
"Azores Summer Time": "AZOST",
"Azores Time": "AZOT",
"Bangladesh Standard Time": "BST",
"Bhutan Time": "BTT",
"Bolivia Time": "BOT",
// ...
};
```
**Caution:** Although abbreviations can be easy to lookup, they can be misleading. For example: CST can refer to Central Standard Time (-06.00 UTC), China Standard Time (+06.00 UTC) or Cuba Standard Time (-05.00 UTC). And abbreviation full forms don't directly map to any property in the time zone objects returned by `rawTimeZones` or `getTimeZones()`.
## Notes
- We provide two cities when grouping happens, ranked by population
- We provide alternative names ("Pacific Time" for "America/Los_Angeles") and remove "Standard", "Daylight" or "Summer" from them
- If you're using this to build a time zone selector and saving to a database then:
- make sure to save the `name` attribute (`America/Los_Angeles`) in your database
- when displaying the select with a default value from your database, either select the time zone name that matches, or if the time zone name is part of the group. Example:
```js
const value = timeZones.find((timeZone) => {
return dbData.timeZone === timeZone.name || timeZone.group.includes(dbData.timeZone);
});
```