51 lines
1.3 KiB
JavaScript
51 lines
1.3 KiB
JavaScript
|
/**
|
||
|
|
* @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.
|
||
|
|
*/
|
||
|
|
|
||
|
|
'use strict';
|
||
|
|
|
||
|
|
// MODULES //
|
||
|
|
|
||
|
|
var isString = require( '@stdlib/assert/is-string' ).isPrimitive;
|
||
|
|
var RE_EXTNAME = require( '@stdlib/regexp/extname' ).REGEXP;
|
||
|
|
|
||
|
|
|
||
|
|
// MAIN //
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns a filename extension.
|
||
|
|
*
|
||
|
|
* @param {string} filename - filename
|
||
|
|
* @throws {TypeError} must provide a string primitive
|
||
|
|
* @returns {string} filename extension
|
||
|
|
*
|
||
|
|
* @example
|
||
|
|
* var ext = extname( 'index.js' );
|
||
|
|
* // returns '.js'
|
||
|
|
*/
|
||
|
|
function extname( filename ) {
|
||
|
|
if ( !isString( filename ) ) {
|
||
|
|
throw new TypeError( 'invalid argument. Filename must be a primitive string. Value: `' + filename + '`.' );
|
||
|
|
}
|
||
|
|
return RE_EXTNAME.exec( filename )[ 1 ];
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
// EXPORTS //
|
||
|
|
|
||
|
|
module.exports = extname;
|