Mime

A comprehensive, compact MIME type module.

Version 2 Notes

Version 2 is a breaking change from 1.x as the semver implies. Specifically:

• lookup()renamed togetType()
• extension()renamed togetExtension()
• charset()and load()methods have been removed

If you prefer the legacy version of this module please npm install mime@^1. Version 1 docs may be found here .

Install

NPM

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npm install mime

Browser

It is recommended that you use a bundler such as webpack or browserify to package your code. However, browser-ready versions are available via wzrd.in. Eg For the full version:

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<script src="https://wzrd.in/standalone/mime@latest"></script>
<script>
mime.getType(...); // etc.
<script>

Or, for the mime/liteversion:

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<script src="https://wzrd.in/standalone/mime%2flite@latest"></script>
<script>
mimelite.getType(...); // (Note `mimelite` here)
<script>

Quick Start

For the full version (800+ MIME types, 1,000+ extensions):

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const mime = require('mime');

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

See Mime API below for API details.

Lite Version

There is also a "lite" version of this module that omits vendor-specific ( */vnd.*) and experimental ( */x-*) types. It weighs in at ~2.5KB, compared to 8KB for the full version. To load the lite version:

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

Mime .vs. mime-types .vs. mime-db modules

For those of you wondering about the difference between these [popular] NPM modules, here's a brief rundown ...

mime-dbis "the source of truth" for MIME type information. It is not an API. Rather, it is a canonical dataset of mime type definitions pulled from IANA, Apache, NGINX, and custom mappings submitted by the Node.js community.

mime-typesis a thin wrapper around mime-db that provides an API drop-in compatible(ish) with mime @ < v1.3.6API.

mimeis, as of v2, a self-contained module bundled with a pre-optimized version of the mime-dbdataset. It provides a simplified API with the following characteristics:

• Intelligently resolved type conflicts (See mime-score for details)
• Method naming consistent with industry best-practices
• Compact footprint. Eg The minified+compressed sizes of the various modules:

Module	Size
mime-db	18 KB
mime-types	same as mime-db
mime	8 KB
mime/lite	2 KB

Mime API

Both require('mime')and require('mime/lite')return instances of the MIME class, documented below.

new Mime(typeMap, ... more maps)

Most users of this module will not need to create Mime instances directly. However if you would like to create custom mappings, you may do so as follows ...

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

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

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

If more than one map argument is provided, each map is define()ed (see below), in order.

mime.getType(pathOrExtension)

Get mime type for the given path or extension. Eg

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mime.getType('js');             // ⇨ 'application/javascript'
mime.getType('json');           // ⇨ 'application/json'

mime.getType('txt');            // ⇨ 'text/plain'
mime.getType('dir/text.txt');   // ⇨ 'text/plain'
mime.getType('dir\\text.txt');  // ⇨ 'text/plain'
mime.getType('.text.txt');      // ⇨ 'text/plain'
mime.getType('.txt');           // ⇨ 'text/plain'

nullis returned in cases where an extension is not detected or recognized

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

mime.getExtension(type)

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

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

mime.define(typeMap[, force = false])

Define [more] type mappings.

typeMapis a map of type -> extensions, as documented in new Mime, above.

By default this method will throw an error if you try to map a type to an extension that is already assigned to another type. Passing truefor the forceargument will suppress this behavior (overriding any previous mapping).

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

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

Command Line

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mime [path_or_extension]

Eg

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> mime scripts/jquery.js
application/javascript

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