try2tostring.js (1274B)
1 /** 2 * @license Apache-2.0 3 * 4 * Copyright (c) 2018 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 toStr = require( './tostring.js' ); 24 25 26 // VARIABLES // 27 28 var RE = /^Symbol\(.*\)$/; 29 30 31 // MAIN // 32 33 /** 34 * Attempts to call a `Symbol` method. 35 * 36 * @private 37 * @param {*} value - value to test 38 * @returns {boolean} boolean indicating if able to call a `Symbol` method 39 */ 40 function test( value ) { 41 try { 42 return ( 43 // Objects created via `Object.create( null )` have no `valueOf()` method: 44 typeof value.valueOf() === 'symbol' && 45 46 // Test output of a non-generic method: 47 RE.test( toStr( value ) ) 48 ); 49 } catch ( err ) { // eslint-disable-line no-unused-vars 50 return false; 51 } 52 } 53 54 55 // EXPORTS // 56 57 module.exports = test;