Getting the default file extension for a content-type in JavaScript?

Question

If I have a content-type, how can I get its default file extension?

For example, given one of these content-types, I should get the following file extensions:

+------------------------+----------------+
|      Content-Type      | File Extension |
+------------------------+----------------+
| text/plain             | .txt           |
| application/javascript | .js            |
| application/gzip       | .gz            |
+------------------------+----------------+

If there is no way to get these extensions automatically in JavaScript, my next solution would be to create a simple relationship between content-type and file extension in a JavaScript array. Therefore, I would accept an answer which has a simple table/database of the most common content-type and file extensions.

Answer 1

If you want to roll your own MIME -> extension mapping (rather than using a package), this list would be a good start: https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types/Common_types

The full list of all official MIME types (linked from the article above) can be found here: https://www.iana.org/assignments/media-types/media-types.xhtml

Answer 2

export const FileMimeType = {
  'audio/x-mpeg': 'mpega',
  'application/postscript': 'ps',
  'audio/x-aiff': 'aiff',
  'application/x-aim': 'aim',
  'image/x-jg': 'art',
  'video/x-ms-asf': 'asx',
  'audio/basic': 'ulw',
  'video/x-msvideo': 'avi',
  'video/x-rad-screenplay': 'avx',
  'application/x-bcpio': 'bcpio',
  'application/octet-stream': 'exe',
  'image/bmp': 'dib',
  'text/html': 'html',
  'application/x-cdf': 'cdf',
  'application/pkix-cert': 'cer',
  'application/java': 'class',
  'application/x-cpio': 'cpio',
  'application/x-csh': 'csh',
  'text/css': 'css',
  'application/msword': 'doc',
  'application/xml-dtd': 'dtd',
  'video/x-dv': 'dv',
  'application/x-dvi': 'dvi',
  'application/vnd.ms-fontobject': 'eot',
  'text/x-setext': 'etx',
  'image/gif': 'gif',
  'application/x-gtar': 'gtar',
  'application/x-gzip': 'gz',
  'application/x-hdf': 'hdf',
  'application/mac-binhex40': 'hqx',
  'text/x-component': 'htc',
  'image/ief': 'ief',
  'text/vnd.sun.j2me.app-descriptor': 'jad',
  'application/java-archive': 'jar',
  'text/x-java-source': 'java',
  'application/x-java-jnlp-file': 'jnlp',
  'image/jpeg': 'jpg',
  'application/javascript': 'js',
  'text/plain': 'txt',
  'application/json': 'json',
  'audio/midi': 'midi',
  'application/x-latex': 'latex',
  'audio/x-mpegurl': 'm3u',
  'image/x-macpaint': 'pnt',
  'text/troff': 'tr',
  'application/mathml+xml': 'mathml',
  'application/x-mif': 'mif',
  'video/quicktime': 'qt',
  'video/x-sgi-movie': 'movie',
  'audio/mpeg': 'mpa',
  'video/mp4': 'mp4',
  'video/mpeg': 'mpg',
  'video/mpeg2': 'mpv2',
  'application/x-wais-source': 'src',
  'application/x-netcdf': 'nc',
  'application/oda': 'oda',
  'application/vnd.oasis.opendocument.database': 'odb',
  'application/vnd.oasis.opendocument.chart': 'odc',
  'application/vnd.oasis.opendocument.formula': 'odf',
  'application/vnd.oasis.opendocument.graphics': 'odg',
  'application/vnd.oasis.opendocument.image': 'odi',
  'application/vnd.oasis.opendocument.text-master': 'odm',
  'application/vnd.oasis.opendocument.presentation': 'odp',
  'application/vnd.oasis.opendocument.spreadsheet': 'ods',
  'application/vnd.oasis.opendocument.text': 'odt',
  'application/vnd.oasis.opendocument.graphics-template': 'otg',
  'application/vnd.oasis.opendocument.text-web': 'oth',
  'application/vnd.oasis.opendocument.presentation-template': 'otp',
  'application/vnd.oasis.opendocument.spreadsheet-template': 'ots',
  'application/vnd.oasis.opendocument.text-template': 'ott',
  'application/ogg': 'ogx',
  'video/ogg': 'ogv',
  'audio/ogg': 'spx',
  'application/x-font-opentype': 'otf',
  'audio/flac': 'flac',
  'application/annodex': 'anx',
  'audio/annodex': 'axa',
  'video/annodex': 'axv',
  'application/xspf+xml': 'xspf',
  'image/x-portable-bitmap': 'pbm',
  'image/pict': 'pict',
  'application/pdf': 'pdf',
  'image/x-portable-graymap': 'pgm',
  'audio/x-scpls': 'pls',
  'image/png': 'png',
  'image/x-portable-anymap': 'pnm',
  'image/x-portable-pixmap': 'ppm',
  'application/vnd.ms-powerpoint': 'pps',
  'image/vnd.adobe.photoshop': 'psd',
  'image/x-quicktime': 'qtif',
  'image/x-cmu-raster': 'ras',
  'application/rdf+xml': 'rdf',
  'image/x-rgb': 'rgb',
  'application/vnd.rn-realmedia': 'rm',
  'application/rtf': 'rtf',
  'text/richtext': 'rtx',
  'application/font-sfnt': 'sfnt',
  'application/x-sh': 'sh',
  'application/x-shar': 'shar',
  'application/x-stuffit': 'sit',
  'application/x-sv4cpio': 'sv4cpio',
  'application/x-sv4crc': 'sv4crc',
  'image/svg+xml': 'svgz',
  'application/x-shockwave-flash': 'swf',
  'application/x-tar': 'tar',
  'application/x-tcl': 'tcl',
  'application/x-tex': 'tex',
  'application/x-texinfo': 'texinfo',
  'image/tiff': 'tiff',
  'text/tab-separated-values': 'tsv',
  'application/x-font-ttf': 'ttf',
  'application/x-ustar': 'ustar',
  'application/voicexml+xml': 'vxml',
  'image/x-xbitmap': 'xbm',
  'application/xhtml+xml': 'xhtml',
  'application/vnd.ms-excel': 'xls',
  'application/xml': 'xsl',
  'image/x-xpixmap': 'xpm',
  'application/xslt+xml': 'xslt',
  'application/vnd.mozilla.xul+xml': 'xul',
  'image/x-xwindowdump': 'xwd',
  'application/vnd.visio': 'vsd',
  'audio/x-wav': 'wav',
  'image/vnd.wap.wbmp': 'wbmp',
  'text/vnd.wap.wml': 'wml',
  'application/vnd.wap.wmlc': 'wmlc',
  'text/vnd.wap.wmlsc': 'wmls',
  'application/vnd.wap.wmlscriptc': 'wmlscriptc',
  'video/x-ms-wmv': 'wmv',
  'application/font-woff': 'woff',
  'application/font-woff2': 'woff2',
  'model/vrml': 'wrl',
  'application/wspolicy+xml': 'wspolicy',
  'application/x-compress': 'z',
  'application/zip': 'zip'
};

to use this provide mime type to object

console.log(FileMimeType[image/jpeg])

Answer 3

There is a best package is

mime-db lib npm

var mimeDb = require("mime-db")

usage(it return object)

var data = mimeDb['image/x-icon']
console.log(data)

To get extenstions

 console.log(data.extensions[0])

another one is mime-types derived from mime-db

mime types

but while i use mime types little bugy in getting extension image/x-icon

Answer 4

from nginx

types {
    text/html                             html htm shtml;
    text/css                              css;
    text/xml                              xml;
    image/gif                             gif;
    image/jpeg                            jpeg jpg;
    application/x-javascript              js;
    application/atom+xml                  atom;
    application/rss+xml                   rss;

    text/mathml                           mml;
    text/plain                            txt;
    text/vnd.sun.j2me.app-descriptor      jad;
    text/vnd.wap.wml                      wml;
    text/x-component                      htc;

    image/png                             png;
    image/tiff                            tif tiff;
    image/vnd.wap.wbmp                    wbmp;
    image/x-icon                          ico;
    image/x-jng                           jng;
    image/x-ms-bmp                        bmp;
    image/svg+xml                         svg;
    image/webp                            webp;

    application/java-archive              jar war ear;
    application/mac-binhex40              hqx;
    application/msword                    doc;
    application/pdf                       pdf;
    application/postscript                ps eps ai;
    application/rtf                       rtf;
    application/vnd.ms-excel              xls;
    application/vnd.ms-powerpoint         ppt;
    application/vnd.wap.wmlc              wmlc;
    application/vnd.google-earth.kml+xml  kml;
    application/vnd.google-earth.kmz      kmz;
    application/x-7z-compressed           7z;
    application/x-cocoa                   cco;
    application/x-java-archive-diff       jardiff;
    application/x-java-jnlp-file          jnlp;
    application/x-makeself                run;
    application/x-perl                    pl pm;
    application/x-pilot                   prc pdb;
    application/x-rar-compressed          rar;
    application/x-redhat-package-manager  rpm;
    application/x-sea                     sea;
    application/x-shockwave-flash         swf;
    application/x-stuffit                 sit;
    application/x-tcl                     tcl tk;
    application/x-x509-ca-cert            der pem crt;
    application/x-xpinstall               xpi;
    application/xhtml+xml                 xhtml;
    application/zip                       zip;

    application/octet-stream              bin exe dll;
    application/octet-stream              deb;
    application/octet-stream              dmg;
    application/octet-stream              eot;
    application/octet-stream              iso img;
    application/octet-stream              msi msp msm;

    audio/midi                            mid midi kar;
    audio/mpeg                            mp3;
    audio/ogg                             ogg;
    audio/x-realaudio                     ra;

    video/3gpp                            3gpp 3gp;
    video/mpeg                            mpeg mpg;
    video/quicktime                       mov;
    video/x-flv                           flv;
    video/x-mng                           mng;
    video/x-ms-asf                        asx asf;
    video/x-ms-wmv                        wmv;
    video/x-msvideo                       avi;
    video/mp4                             m4v mp4;
}

Answer 5

For Node applications, there is a more up-to-date answer now, which is to use the mime-types NPM package, e.g.:

var mime = require('mime-types'),
    fileExtension = mime.extension('text/plain');