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mime-types

> 编程语言
Open source

The ultimate javascript content-type utility.

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About

The ultimate javascript content-type utility.

mime-types

The ultimate javascript content-type utility.

Similar to the [email protected] 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

Note on MIME Type Data and Semver

This package considers the programmatic api as the semver compatibility. Additionally, the package which provides the MIME data for this package (mime-db) also considers it's programmatic api as the semver contract. This means the MIME type resolution is not considered in the semver bumps.

In the past the version of mime-db was pinned to give two decision points when adopting MIME data changes. This is no longer true. We still update the mime-db package here as a minor release when necessary, but will use a ^ range going forward. This means that if you want to pin your mime-db data you will need to do it in your application. While this expectation was not set in docs until now, it is how the package operated, so we do not feel this is a breaking change.

If you wish to pin your mime-db version you can do that with overrides via your package manager of choice. See their documentation for how to correctly configure that.

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') // 'text/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

GitHub Issues· 27 open

View all on GitHub
  • #23

    Multiple Mime-Types for an extension

    enhancementUpdated Jul 25, 2026
  • #156

    Invalid MIME type in the README

    Updated Jul 23, 2026
  • #157

    Unecessary dependency to node:path prevent to be used in browser.

    questionUpdated Dec 22, 2025

Highlights

  • •__No fallbacks.__ Instead of naively returning the first available type,
  • •No new Mime() business, so you could do var lookup = require('mime-types').lookup.
  • •No .define() functionality
  • •Bug fixes for .lookup(path)

> Tags

JavaScriptjavascriptmimemime-typesnodejs

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> Details

PublishedAug 1, 2026
UpdatedSep 17, 2026
Category编程语言
PricingOpen source

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