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.

Similar to the mime@1.x module, 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.
• No .define() functionality
• Bug fixes for .lookup(path)

Otherwise, the API is compatible with mime 1.x.

Install

This is a Node.js module available through the npm registry. Installation is done using the npm install command:

$ npm install mime-types

Adding Types

All mime types are based on mime-db, so open a PR there if you'd like to add mime types.

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/markdown'
mime.lookup('file.html') // 'text/html'
mime.lookup('folder/file.js') // 'application/javascript'
mime.lookup('folder/.htaccess') // false

mime.lookup('cats') // false

mime.contentType(type)

Create a full content-type header given a content-type or extension. When given an extension, mime.lookup is used to get the matching content-type, otherwise the given content-type is used. Then if the content-type does not already have a charset parameter, mime.charset is used to get the default charset and add to the returned content-type.

mime.contentType('markdown') // 'text/x-markdown; charset=utf-8'
mime.contentType('file.json') // 'application/json; charset=utf-8'
mime.contentType('text/html') // 'text/html; charset=utf-8'
mime.contentType('text/html; charset=iso-8859-1') // 'text/html; charset=iso-8859-1'

// from a full path
mime.contentType(path.extname('/path/to/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/markdown') // 'UTF-8'

var type = mime.types[extension]

A map of content-types by extension.

[extensions...] = mime.extensions[type]

A map of extensions by content-type.

License

MIT