日本語のREADMEはこちらです: README.ja.md

A comprehensive, compact MIME type module.

npm install mime

The full version includes 800+ MIME types and 1,000+ extensions.

const mime = require('mime');

mime.getType('txt');                    // 'text/plain'
mime.getExtension('text/plain');        // 'txt'

It is recommended that you use a bundler such as webpack or browserify. However, browser-ready versions are available via skypack.dev:

<!-- Full version -->
<script type="module">
  import mime from "https://cdn.skypack.dev/mime";
</script>

<!-- Lite version -->
<script type="module">
  import mime from "https://cdn.skypack.dev/mime/lite";
</script>

The "lite" version of this module omits vendor-specific (*/vnd.*) and experimental (*/x-*) types. It weighs in at ~2KB, compared to 8KB for the full version.

const mime = require('mime/lite');

• mime-db is the source of truth for MIME type information. It is a canonical dataset of MIME type definitions from IANA, Apache, NGINX, and the Node.js community. It is not an API.
• mime-types is a thin wrapper around mime-db that provides a legacy-compatible API.
• mime is a self-contained module with a pre-optimized version of the mime-db dataset. It provides a simplified API that intelligently resolves type conflicts using mime-score.

Both require('mime') and require('mime/lite') return instances of the Mime class.

Note: Inputs to this API are case-insensitive. Outputs (returned values) will be lowercase.

Get the MIME type for a given path or extension.

mime.getType('js');             // 'application/javascript'
mime.getType('dir/text.txt');   // 'text/plain'
mime.getType('dir\\text.txt');  // 'text/plain'
mime.getType('.html');          // 'text/html'

Returns null if the extension is not detected or recognized.

mime.getType('foo/txt');        // null
mime.getType('bogus_type');     // null

Get the extension for a given MIME type. Charset options (often included in Content-Type headers) are ignored.

mime.getExtension('text/plain');               // 'txt'
mime.getExtension('application/json');         // 'json'
mime.getExtension('text/html; charset=utf8');  // 'html'

Create a new Mime instance with custom mappings.

// Require Mime class
const Mime = require('mime/Mime');

// Define mime type -> extensions map
const typeMap = {
  'text/abc': ['abc', 'alpha'],
  'text/def': ['leppard']
};

// Create and use Mime instance
const myMime = new Mime(typeMap);
myMime.getType('alpha');          // 'text/abc'
myMime.getExtension('text/def');  // 'leppard'

Define more type mappings.

By default, this method will throw an error if you try to map an extension that is already assigned to another type. Pass true for the force argument to override previous mappings.

mime.define({'text/x-abc': ['abc', 'abcd']});

mime.getType('abcd');            // 'text/x-abc'
mime.getExtension('text/x-abc')  // 'abc'

$ mime path/to/file.json
application/json

$ mime .html
text/html

$ mime -r application/json
json

MIT License