mime/README.md

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# Mime

A comprehensive, compact MIME type module.

[![Build Status](https://travis-ci.org/broofa/mime.svg?branch=master)](https://travis-ci.org/broofa/mime)

## Version 2 Notes

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

* `lookup()` renamed to `getType()`
* `extension()` renamed to `getExtension()`
* `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](https://github.com/broofa/mime/tree/v1.4.0).

## Install

### NPM
```
npm install mime
```

### Browser

It is recommended that you use a bundler such as
[webpack](https://webpack.github.io/) or [browserify](http://browserify.org/) to
package your code.  However, browser-ready versions are available via wzrd.in.
E.g. For the full version:

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

Or, for the `mime/lite` version:

    <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):

```javascript
const mime = require('mime');

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

See [Mime API](#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:

```javascript
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-db`](https://github.com/jshttp/mime-db) is "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-types`](https://github.com/jshttp/mime-types) is a thin
wrapper around mime-db that provides an API drop-in compatible(ish) with `mime @ < v1.3.6` API.

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

* Intelligently resolved type conflicts (See [mime-score](https://github.com/broofa/mime-score) for details)
* Method naming consistent with industry best-practices
* Compact footprint.  E.g. 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.

Note: Inputs to this API are case-insensitive.  Outputs (returned values) will
be lowercase.

### 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
...

```javascript
// 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.  E.g.

```javascript
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'
```

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

```javascript
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.

```javascript
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.

`typeMap` is 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 `true` for the
`force` argument will suppress this behavior (overriding any previous mapping).

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

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

## Command Line

    mime [path_or_extension]

E.g.

    > mime scripts/jquery.js
    application/javascript

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