bcp-47-match
Match BCP 47 language tags with language ranges per RFC 4647.
Contents
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 14.14+, 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'
const tags = ['en-GB', 'de-CH', 'en', 'de']
console.log(basicFilter(tags, '*'))
console.log(basicFilter(tags, 'en'))
console.log(basicFilter(tags, 'en-GB'))
console.log(basicFilter(tags, ['en-GB', 'en']))
console.log(basicFilter(tags, 'jp'))
console.log(extendedFilter(tags, '*'))
console.log(extendedFilter(tags, 'en'))
console.log(extendedFilter(tags, 'en-GB'))
console.log(extendedFilter(tags, '*-GB'))
console.log(extendedFilter(tags, ['en-GB', 'en']))
console.log(extendedFilter(tags, 'jp'))
console.log(lookup(tags, 'en'))
console.log(lookup(tags, 'en-GB'))
console.log(lookup(tags, ['en-GB', 'en']))
console.log(lookup(tags, ['en', 'en-GB']))
console.log(lookup(tags, 'jp'))
API
This package exports the identifier 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
(string
or Array<string>
)
— list of BCP 47 tagsranges
(string
or Array<string>
, default: '*'
)
— list of RFC 4647
basic ranges
(aka, matching /^(\*|[a-z]{1,8}(-[a-z0-9]{1,8})*)$/i
)
Returns
Possibly empty list of matching tags in the order they matched
(Array<string>
).
extendedFilter(tags[, ranges='*'])
👉 Note: See
Extended Filtering spec
Match language tags to a list of extended ranges.
Searches for matches between the first range and all tags, and continues
with further ranges.
View matching table
Extended Filter | * | de | de-CH | de-DE | de-*-DE | *-CH |
---|
de | ✔︎ | ✔︎ | | | | |
de-CH | ✔︎ | ✔︎ | ✔︎ | | | ✔︎ |
de-CH-1996 | ✔︎ | ✔︎ | ✔︎ | | | ✔︎ |
de-DE | ✔︎ | ✔︎ | | ✔︎ | ✔︎ | |
de-DE-1996 | ✔︎ | ✔︎ | | ✔︎ | ✔︎ | |
de-DE-x-goethe | ✔︎ | ✔︎ | | ✔︎ | ✔︎ | |
de-Deva | ✔︎ | ✔︎ | | | | |
de-Deva-DE | ✔︎ | ✔︎ | | ✔︎ | ✔︎ | |
de-Latf-DE | ✔︎ | ✔︎ | | ✔︎ | ✔︎ | |
de-Latn-DE | ✔︎ | ✔︎ | | ✔︎ | ✔︎ | |
de-Latn-DE-1996 | ✔︎ | ✔︎ | | ✔︎ | ✔︎ | |
de-x-DE | ✔︎ | ✔︎ | | | | |
en | ✔︎ | | | | | |
en-GB | ✔︎ | | | | | |
zh | ✔︎ | | | | | |
zh-Hans | ✔︎ | | | | | |
zh-Hant | ✔︎ | | | | | |
Parameters
tags
(string
or Array<string>
)
— list of BCP 47 tagsranges
(string
or Array<string>
, default: '*'
)
— list of RFC 4647 extended ranges
(aka, matching /^(\*|[a-z]{1,8})(-(\*|[a-z0-9]{1,8}))*$/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
(string
or Array<string>
)
— list of BCP 47 tagsranges
(string
or Array<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.
It exports no additional types.
Compatibility
This package is at least compatible with all maintained versions of Node.js.
As of now, that is Node.js 14.14+ and 16.0+.
It also works in Deno and modern browsers.
Security
This package is safe.
Related
Contribute
Yes please!
See How to Contribute to Open Source.
License
MIT © Titus Wormer