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    bcp-47-match
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    2.0.2 • Public • Published

    bcp-47-match

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    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 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 (string or Array<string>) — list of BCP 47 tags
    • ranges (string or Array<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 (string or Array<string>) — list of BCP 47 tags
    • ranges (string or Array<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 (string or Array<string>) — list of BCP 47 tags
    • ranges (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.

    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

    Contribute

    Yes please! See How to Contribute to Open Source.

    License

    MIT © Titus Wormer

    Install

    npm i bcp-47-match

    DownloadsWeekly Downloads

    70,148

    Version

    2.0.2

    License

    MIT

    Unpacked Size

    18 kB

    Total Files

    5

    Last publish

    Collaborators

    • wooorm