main.js (3182B)
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 getOwnPropertyDescriptors = require( './../../property-descriptors' ); 24 var getOwnPropertySymbols = require( './../../property-symbols' ); 25 var getPrototypeOf = require( './../../get-prototype-of' ); 26 var objectKeys = require( './../../keys' ); 27 var defineProperty = require( './../../define-property' ); 28 var hasOwnProp = require( '@stdlib/assert/has-own-property' ); 29 30 31 // MAIN // 32 33 /** 34 * Returns an object's own and inherited property descriptors. 35 * 36 * ## Notes 37 * 38 * - In contrast to the built-in `Object.getOwnPropertyDescriptors()`, this function returns an empty object if provided `undefined` or `null`, rather than throwing an error. 39 * 40 * @param {*} value - input object 41 * @returns {Object} own and inherited property descriptors 42 * 43 * @example 44 * var obj = { 45 * 'beep': 'boop', 46 * 'foo': 3.14 47 * }; 48 * 49 * var desc = propertyDescriptorsIn( obj ); 50 * // returns { 'beep': {...}, 'foo': {...}, ... } 51 */ 52 function propertyDescriptorsIn( value ) { 53 var desc; 54 var keys; 55 var obj; 56 var tmp; 57 var i; 58 59 if ( value === null || value === void 0 ) { 60 return {}; 61 } 62 // Cast the value to an object: 63 obj = Object( value ); 64 65 // Walk the prototype chain collecting all property descriptors... 66 desc = {}; 67 do { 68 tmp = getOwnPropertyDescriptors( obj ); 69 keys = objectKeys( tmp ); 70 for ( i = 0; i < keys.length; i++ ) { 71 // The first encountered property descriptor for a property name always takes precedence... 72 if ( !hasOwnProp( desc, keys[ i ] ) ) { 73 // The following is equivalent to `desc[ keys[i] ] = {...}`, but accounts for the possibility of a "poisoned" `Object` prototype (i.e., an `Object.prototype` having a property with a setter which throws). 74 defineProperty( desc, keys[ i ], { 75 'configurable': true, 76 'enumerable': true, 77 'writable': true, 78 'value': tmp[ keys[ i ] ] 79 }); 80 } 81 } 82 keys = getOwnPropertySymbols( tmp ); 83 for ( i = 0; i < keys.length; i++ ) { 84 // The first encountered property descriptor for a symbol property always takes precedence... 85 if ( !hasOwnProp( desc, keys[ i ] ) ) { 86 // The following is equivalent to `desc[ keys[i] ] = {...}`, but accounts for the possibility of a "poisoned" `Object` prototype (i.e., an `Object.prototype` having a property with a setter which throws). 87 defineProperty( desc, keys[ i ], { 88 'configurable': true, 89 'enumerable': true, 90 'writable': true, 91 'value': tmp[ keys[ i ] ] 92 }); 93 } 94 } 95 obj = getPrototypeOf( obj ); 96 } while ( obj ); 97 98 return desc; 99 } 100 101 102 // EXPORTS // 103 104 module.exports = propertyDescriptorsIn;