parse abbreviated, sloppy, and informal timezone names

npm install timezone-soft

_{by Spencer Kelly}

^{(formerly called 'spacetime-informal')}

1import soft from 'timezone-soft'
2
3// get an IANA tz from user input
4let timezones = soft('milwaukee')[0]
5/*[{
6    iana: 'America/Chicago',
7    standard: { name: 'Central Standard Time', abbrev: 'CST' },
8    daylight: { name: 'Central Daylight Time', abbrev: 'CDT' }
9  }
10]*/

IANA timezone codes are the official reference for timezone information, and is what you should use, whenever possible.

Humans though, are goofballs, and use a whole different informal scheme:

• In (North) America: PST, MST, EST...
• in Europe (lately): WEST, CEST, EEST...
• in Africa: EAT, CAT, WAST...
• in Australia: AWST, AEDT, ACST...

these line-up with the IANA codes sometimes.

...other times they don't.

These names also collide -

'IST' is used to mean:

• 'Indian Stardard Time'
• 'Irish Stardard Time'
• 'Israeli Stardard Time'

These names also produce all-sorts of ambiguities, regarding DST-changes-

Both Winnipeg and Mexico City are CST, but have a much different DST schedule:

(thanks timeanddate.com!)

-of course, there's a bunch of political/historical/disputed stuff going on, too. Apologies if this library steps into that unknowingly.

...so that's what we're trying to fix - to 'soften' this exchange, between human and IANA timezone nomenclature, using some opinionated-but-common-sense rules and decision-making.

It was originally built for use in the spacetime timezone library.

Usage

1const soft = require('timezone-soft')
2
3soft('EST')
4// 'America/New_York'
5
6soft('central')
7// 'America/Chicago'
8
9soft('venezuela')
10// 'America/Caracas'
11
12soft('south east asia')
13// 'Asia/Bangkok'

Typescript/Deno/Webpack:

1import soft from 'timezone-soft'

it was built to be as forgiving as possible, and return the most common-sense IANA timezone id from user-input.

DST

Often, the proper timezone name will depend on which date you are referencing. You can reckon this pretty-easily with spacetime, like this:

1const spacetime = require('spacetime')
2const soft = require('timezone-soft')
3
4let display = soft('montreal')[0]
5let show = display.standard.abbrev
6
7// are we in standard time, or daylight time?
8let s = spacetime.now(display.iana)
9if (display.daylight && s.isDST()) {
10  show = display.daylight.abbrev
11}
12console.log(s.time() + ' ' + show)
13// '4:20pm EDT'

work-in-progress!

See also

• TimeZoneNames .NET Standard Library by Matt Johnson-Pint

MIT