main.js (1536B)
1 /** 2 * @license Apache-2.0 3 * 4 * Copyright (c) 2021 The Stdlib Authors. 5 * 6 * Licensed under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 19 'use strict'; 20 21 // MODULES // 22 23 var isFunction = require( './../../is-function' ); 24 25 26 // VARIABLES // 27 28 var RE_CLASS = /^\s*class\s/; 29 30 // Using `Function#toString` bypasses a value's own `toString` method to provide an extra, but not security proof, precaution to prevent a provided function from impersonating a class: 31 var fcn2str = Function.prototype.toString; 32 33 34 // MAIN // 35 36 /** 37 * Tests if a value is a class. 38 * 39 * @param {*} value - value to test 40 * @returns {boolean} boolean indicating whether value is a class 41 * 42 * @example 43 * var bool = isClass( class Person {} ); 44 * // returns true 45 * 46 * @example 47 * var bool = isClass( function Person() {} ); 48 * // returns false 49 * 50 * @example 51 * var bool = isClass( null ); 52 * // returns false 53 */ 54 function isClass( value ) { 55 var str; 56 if ( !isFunction( value ) ) { 57 return false; 58 } 59 str = fcn2str.call( value ); 60 return RE_CLASS.test( str ); 61 } 62 63 64 // EXPORTS // 65 66 module.exports = isClass;