mime-types

What is mime-types?

The mime-types npm package is a utility for resolving file extensions to MIME types and vice versa. It is based on the mime-db dataset, which is a comprehensive set of MIME type definitions.

What are mime-types's main functionalities?

Lookup MIME type for a file extension

This feature allows you to find the MIME type for a given file extension. If the extension has a MIME type in the database, it will return it as a string; otherwise, it will return false.

const mime = require('mime-types');
const mimeType = mime.lookup('json'); // 'application/json'

Determine the default extension for a MIME type

This feature enables you to find the default file extension for a given MIME type. If the MIME type has an associated extension, it will return it as a string; otherwise, it will return false.

const mime = require('mime-types');
const extension = mime.extension('application/json'); // 'json'

Lookup charset for a MIME type

This feature allows you to find the default charset for a given MIME type, which can be useful when setting the 'Content-Type' header in HTTP responses.

const mime = require('mime-types');
const charset = mime.charset('text/markdown'); // 'UTF-8'

Content-Type parsing

This feature is used to build a full Content-Type header given a MIME type or extension. It will also append the charset parameter when appropriate.

const mime = require('mime-types');
const contentType = mime.contentType('markdown'); // 'text/markdown; charset=utf-8'

Other packages similar to mime-types

mime

The 'mime' package is similar to 'mime-types' and provides MIME type lookup and extension lookup. It differs in that it allows for custom MIME type definitions and has a slightly different API.

file-type

The 'file-type' package is used to detect the file type and MIME type of a Buffer/Uint8Array/ArrayBuffer. Unlike 'mime-types', it does not rely on file extensions and can detect the type of binary content.

README

mime-types

The ultimate javascript content-type utility.

Install

$ npm install mime-types

Similar to node-mime, except:

• No fallbacks. Instead of naively returning the first available type, mime-types simply returns false, so do var type = mime.lookup('unrecognized') || 'application/octet-stream'.
• No new Mime() business, so you could do var lookup = require('mime-types').lookup.
• Additional mime types are added such as jade and stylus. Feel free to add more!
• Browser support via Browserify and Component by converting lists to JSON files.

Otherwise, the API is compatible.

Adding Types

If you'd like to add additional types, simply create a PR adding the type to custom.json and a reference link to the sources.

Do NOT edit mime.json or node.json. Those are pulled using build.js. You should only touch custom.json.

API

var mime = require('mime-types')

All functions return false if input is invalid or not found.

mime.lookup(path)

Lookup the content-type associated with a file.

mime.lookup('json')           // 'application/json'
mime.lookup('.md')            // 'text/x-markdown'
mime.lookup('file.html')      // 'text/html'
mime.lookup('folder/file.js') // 'application/javascript'

mime.lookup('cats') // false

mime.contentType(type)

Create a full content-type header given a content-type or extension.

mime.contentType('markdown')  // 'text/x-markdown; charset=utf-8'
mime.contentType('file.json') // 'application/json; charset=utf-8'

mime.extension(type)

Get the default extension for a content-type.

mime.extension('application/octet-stream') // 'bin'

mime.charset(type)

Lookup the implied default charset of a content-type.

mime.charset('text/x-markdown') // 'UTF-8'

mime.types[extension] = type

A map of content-types by extension.

mime.extensions[type] = [extensions]

A map of extensions by content-type.

mime.define(types)

Globally add definitions. types must be an object of the form:

{
  "<content-type>": [extensions...],
  "<content-type>": [extensions...]
}

See the .json files in lib/ for examples.

License

MIT