Mime

An API for MIME type information.

• All mime-db types
• Compact and dependency-free
• Full TS support

[!Note] mime@4 is now latest. If you're upgrading from mime@3, note the following:

• mime@4 is API-compatible with mime@3, with ~~one~~ two exceptions:
  • Direct imports of mime properties no longer supported
  • mime.define() cannot be called on the default mime object
• ESM module support is required. ESM Module FAQ.
• Requires an ES2020 or newer runtime
• Built-in Typescript types (@types/mime no longer needed)

Installation

npm install mime

Quick Start

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

import mime from 'mime';

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

Lite Version

mime/lite is a drop-in mime replacement, stripped of unofficial ("prs.*", "x-*", "vnd.*") types:

import mime from 'mime/lite';

API

mime.getType(pathOrExtension)

Get mime type for the given file path or extension. E.g.

mime.getType('js');             // ⇨ 'text/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'

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

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

mime.getExtension(type)

Get file extension for the 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'

mime.getAllExtensions(type)

[!Note] New in mime@4

Get all file extensions for the given mime type.

mime.getAllExtensions('image/jpeg'); // ⇨ Set(3) { 'jpeg', 'jpg', 'jpe' }

Custom Mime instances

The default mime objects are immutable. Custom, mutable versions can be created as follows...

new Mime(type map [, type map, ...])

Create a new, custom mime instance. For example, to create a mutable version of the default mime instance:

import { Mime } from 'mime/lite';

import standardTypes from 'mime/types/standard.js';
import otherTypes from 'mime/types/other.js';

const mime = new Mime(standardTypes, otherTypes);

Each argument is passed to the define() method, below. For example new Mime(standardTypes, otherTypes) is synonomous with new Mime().define(standardTypes).define(otherTypes)

mime.define(type map [, force = false])

[!Note] Only available on custom Mime instances

Define MIME type -> extensions.

Attempting to map a type to an already-defined extension will throw unless the force argument is set to true.

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

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

Command Line

Extension -> type

$ mime scripts/jquery.js
text/javascript

Type -> extension

$ mime -r image/jpeg
jpeg