<!-- @license Apache-2.0 Copyright (c) 2018 The Stdlib Authors. Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. --> # Filename Extension > Return a filename extension. <section class="usage"> ## Usage ```javascript var extname = require( '@stdlib/utils/extname' ); ``` #### extname( filename ) Returns a filename extension. ```javascript var ext = extname( 'index.js' ); // returns '.js' ``` </section> <!-- /.usage --> <section class="examples"> ## Examples <!-- eslint no-undef: "error" --> ```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)' ); } } ``` </section> <!-- /.examples --> <section class="links"> </section> <!-- /.links -->