bcp-47-match
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Match BCP 47 language tags with language ranges per RFC 4647
bcp-47-match
Match BCP 47 language tags with language ranges per RFC 4647.
Contents
- What is this?
- When should I use this?
- Install
- Use
-
API
-
basicFilter(tags[, ranges='*']) -
extendedFilter(tags[, ranges='*']) -
lookup(tags, ranges)
-
- Types
- Compatibility
- Security
- Related
- Contribute
- License
What is this?
This package can match BCP 47 language tags with “language ranges” per
RFC 4647.
This is done by the :lang() pseudo class in CSS, the Accept-Language HTTP
header, and a few other places.
When should I use this?
You can use this package if you want to choose a certain document based on language tags.
Install
This package is ESM only. In Node.js (version 12.20+, 14.14+, or 16.0+), install with npm:
npm install bcp-47-match
In Deno with esm.sh:
import * as bcp47Match from 'https://esm.sh/bcp-47-match@2'
In browsers with esm.sh:
<script type="module">
import * as bcp47Match from 'https://esm.sh/bcp-47-match@2?bundle'
</script>
Use
import {basicFilter, extendedFilter, lookup} from 'bcp-47-match'
var tags = ['en-GB', 'de-CH', 'en', 'de']
console.log(basicFilter(tags, '*')) // => [ 'en-GB', 'de-CH', 'en', 'de' ]
console.log(basicFilter(tags, 'en')) // => [ 'en-GB', 'en' ]
console.log(basicFilter(tags, 'en-GB')) // => [ 'en-GB' ]
console.log(basicFilter(tags, ['en-GB', 'en'])) // => [ 'en-GB', 'en' ]
console.log(basicFilter(tags, 'jp')) // => []
console.log(extendedFilter(tags, '*')) // => [ 'en-GB', 'de-CH', 'en', 'de' ]
console.log(extendedFilter(tags, 'en')) // => [ 'en-GB', 'en' ]
console.log(extendedFilter(tags, 'en-GB')) // => [ 'en-GB' ]
console.log(extendedFilter(tags, '*-GB')) // => [ 'en-GB' ]
console.log(extendedFilter(tags, ['en-GB', 'en'])) // => [ 'en-GB', 'en' ]
console.log(extendedFilter(tags, 'jp')) // => []
console.log(lookup(tags, 'en')) // => 'en'
console.log(lookup(tags, 'en-GB')) // => 'en-GB'
console.log(lookup(tags, ['en-GB', 'en'])) // => 'en-GB'
console.log(lookup(tags, ['en', 'en-GB'])) // => 'en'
console.log(lookup(tags, 'jp')) // => undefined
API
This package exports the following identifiers: basicFilter, extendedFilter,
and lookup.
There is no default export.
basicFilter(tags[, ranges='*'])
👉 Note: See Basic Filtering spec
Match language tags to a list of simple ranges. Searches for matches between the first range and all tags, and continues with further ranges. Returns a list of matching tags in the order they matched.
View matching table
| Basic Filter | * |
de |
de-CH |
de-DE |
de-*-DE |
*-CH |
|---|---|---|---|---|---|---|
de |
✔︎ | ✔︎ | ||||
de-CH |
✔︎ | ✔︎ | ✔︎ | |||
de-CH-1996 |
✔︎ | ✔︎ | ✔︎ | |||
de-DE |
✔︎ | ✔︎ | ✔︎ | |||
de-DE-1996 |
✔︎ | ✔︎ | ✔︎ | |||
de-DE-x-goethe |
✔︎ | ✔︎ | ✔︎ | |||
de-Deva |
✔︎ | ✔︎ | ||||
de-Deva-DE |
✔︎ | ✔︎ | ||||
de-Latf-DE |
✔︎ | ✔︎ | ||||
de-Latn-DE |
✔︎ | ✔︎ | ||||
de-Latn-DE-1996 |
✔︎ | ✔︎ | ||||
de-x-DE |
✔︎ | ✔︎ | ||||
en |
✔︎ | |||||
en-GB |
✔︎ | |||||
zh |
✔︎ | |||||
zh-Hans |
✔︎ | |||||
zh-Hant |
✔︎ |
Parameters
-
tags(stringorArray<string>) — list of BCP 47 tags -
ranges(stringorArray<string>) — list of RFC 4647 basic ranges (aka, matching/^(\*|[a-z]{1,8}(-[a-z0-9]{1,8})*)$/i)
Returns
Possibly empty list of matching tags in the order they matched
(Array<string>).
extendedFilter(tags[, ranges='*'])
👉 Note: See Extended Filtering spec
Match language tags to a list of extended ranges. Searches for matches between the first range and all tags, and continues with further ranges.
View matching table
| Extended Filter | * |
de |
de-CH |
de-DE |
de-*-DE |
*-CH |
|---|---|---|---|---|---|---|
de |
✔︎ | ✔︎ | ||||
de-CH |
✔︎ | ✔︎ | ✔︎ | ✔︎ | ||
de-CH-1996 |
✔︎ | ✔︎ | ✔︎ | ✔︎ | ||
de-DE |
✔︎ | ✔︎ | ✔︎ | ✔︎ | ||
de-DE-1996 |
✔︎ | ✔︎ | ✔︎ | ✔︎ | ||
de-DE-x-goethe |
✔︎ | ✔︎ | ✔︎ | ✔︎ | ||
de-Deva |
✔︎ | ✔︎ | ||||
de-Deva-DE |
✔︎ | ✔︎ | ✔︎ | ✔︎ | ||
de-Latf-DE |
✔︎ | ✔︎ | ✔︎ | ✔︎ | ||
de-Latn-DE |
✔︎ | ✔︎ | ✔︎ | ✔︎ | ||
de-Latn-DE-1996 |
✔︎ | ✔︎ | ✔︎ | ✔︎ | ||
de-x-DE |
✔︎ | ✔︎ | ||||
en |
✔︎ | |||||
en-GB |
✔︎ | |||||
zh |
✔︎ | |||||
zh-Hans |
✔︎ | |||||
zh-Hant |
✔︎ |
Parameters
-
tags(stringorArray<string>) — list of BCP 47 tags -
ranges(stringorArray<string>) — list of RFC 4647 extended ranges (aka, matching/^(\*|[a-z]{1,8})(-(\*|[a-z0-9]{1,8}))*$/i)
Returns
Possibly empty list of matching tags in the order they matched
(Array<string>).
lookup(tags, ranges)
👉 Note: See Lookup spec
Find the best language tag that matches a list of ranges. Searches for a match between the first range and all tags, and continues with further ranges. Returns the first match, if any.
View matching table
| Lookup | * |
de |
de-CH |
de-DE |
de-*-DE |
*-CH |
|---|---|---|---|---|---|---|
de |
✔︎︎ | ✔︎︎ | ✔︎ | ✔︎ | ✔︎ | |
de-CH |
✔︎ | ✔︎ | ||||
de-CH-1996 |
✔︎ | |||||
de-DE |
✔︎ | ✔︎ | ||||
de-DE-1996 |
✔︎ | |||||
de-DE-x-goethe |
✔︎ | |||||
de-Deva |
✔︎ | |||||
de-Deva-DE |
✔︎ | |||||
de-Latf-DE |
✔︎ | |||||
de-Latn-DE |
✔︎ | |||||
de-Latn-DE-1996 |
✔︎ | |||||
de-x-DE |
✔︎ | |||||
en |
✔︎ | |||||
en-GB |
✔︎ | |||||
zh |
✔︎ | |||||
zh-Hans |
✔︎ | |||||
zh-Hant |
✔︎ |
Parameters
-
tags(stringorArray<string>) — list of BCP 47 tags -
ranges(stringorArray<string>) — list of RFC 4647 basic ranges (but*is ignored)
Returns
First matching tag in tags, undefined otherwise (string?).
Types
This package is fully typed with TypeScript.
Compatibility
This package is at least compatible with all maintained versions of Node.js. As of now, that is Node.js 12.20+, 14.14+, and 16.0+. It also works in Deno and modern browsers.
Security
This package is safe.
Related
-
wooorm/bcp-47— parse and serialize BCP 47 language tags -
wooorm/bcp-47-normalize— normalize, canonicalize, and format BCP 47 tags -
wooorm/iso-3166— ISO 3166 codes -
wooorm/iso-639-2— ISO 639-2 codes -
wooorm/iso-639-3— ISO 639-3 codes -
wooorm/iso-15924— ISO 15924 codes -
wooorm/un-m49— UN M49 codes
Contribute
Yes please! See How to Contribute to Open Source.
License
MIT © Titus Wormer
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