# Filename Extension
> Return a filename extension.
## Usage
```javascript
var extname = require( '@stdlib/utils/extname' );
```
#### extname( filename )
Returns a filename extension.
```javascript
var ext = extname( 'index.js' );
// returns '.js'
```
## Examples
```javascript
var statSync = require( 'fs' ).statSync;
var path = require( 'path' );
var readDir = require( '@stdlib/fs/read-dir' ).sync;
var extname = require( '@stdlib/utils/extname' );
var files;
var fpath;
var base;
var stat;
var ext;
var i;
base = path.resolve( __dirname, '..' );
files = readDir( base );
for ( i = 0; i < files.length; i++ ) {
fpath = path.join( base, files[ i ] );
stat = statSync( fpath );
if ( !stat.isDirectory() ) {
ext = extname( fpath );
console.log( '%s --> %s', fpath, ext || '(no ext)' );
}
}
```