> Returns true if the given string is a POSIX bracket expression (POSIX character class).
## Install
Install with [npm](https://www.npmjs.com/):
```sh
$ npm install is-posix-bracket --save
```
## Usage
```js
var isPosixBracket = require('is-posix-bracket');
isPosixBracket('[foo:]]');
//=> false
isPosixBracket('[xdigit:]]');
//=> false
isPosixBracket('[[:xdigit:]]');
//=> true
isPosixBracket('[[:xdigit:]]');
//=> true
isPosixBracket('[[:alpha:]123]');
//=> true
isPosixBracket('[[:alpha:]123]');
//=> true
isPosixBracket('[a-c[:digit:]x-z]');
//=> true
isPosixBracket('[:al:]');
//=> true
isPosixBracket('[abc[:punct:][0-9]');
//=> true
```
## Related projects
You might also be interested in these projects:
* [braces](https://www.npmjs.com/package/braces): Fastest brace expansion for node.js, with the most complete support for the Bash 4.3 braces… [more](https://www.npmjs.com/package/braces) | [homepage](https://github.com/jonschlinkert/braces)
* [is-extglob](https://www.npmjs.com/package/is-extglob): Returns true if a string has an extglob. | [homepage](https://github.com/jonschlinkert/is-extglob)
* [is-glob](https://www.npmjs.com/package/is-glob): Returns `true` if the given string looks like a glob pattern or an extglob pattern.… [more](https://www.npmjs.com/package/is-glob) | [homepage](https://github.com/jonschlinkert/is-glob)
* [micromatch](https://www.npmjs.com/package/micromatch): Glob matching for javascript/node.js. A drop-in replacement and faster alternative to minimatch and multimatch. Just… [more](https://www.npmjs.com/package/micromatch) | [homepage](https://github.com/jonschlinkert/micromatch)
## Contributing
Pull requests and stars are always welcome. For bugs and feature requests, [please create an issue](https://github.com/jonschlinkert/is-posix-bracket/issues/new).
## Building docs
Generate readme and API documentation with [verb](https://github.com/verbose/verb):
```sh
$ npm install verb && npm run docs
```
Or, if [verb](https://github.com/verbose/verb) is installed globally: