tzdb

This is a list and npm package of:

"simplified" IANA 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

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.

NPM package

Installation:

npm add @vvo/tzdb

Usage:

import { getTimeZones, rawTimeZones, timeZonesNames } from "@vvo/tzdb";

API

getTimeZones()

const timeZones = getTimeZones();

This method returns an array of time zones objects:

[
  // ...
  {
    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:

{
  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"
}

rawTimeZones

This is an array of time zone objects without the current time information:

[
  // ...
  {
    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",
  },
  // ...
];

timeZonesNames

This is an array of time zone names:

[
  // ...
  "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",
  // ...
];

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:

const value = timeZones.find((timeZone) => {
  return dbData.timeZone === timeZone.name || timeZone.group.includes(dbData.timeZone);
});