ECMAScript5新特性之获取对象特有的属性

'use strict';
// 父类
function Fruit(){
                
}
Fruit.prototype.name = '水果';
// 子类
function Apple(desc){
    this.desc = desc;
}
// 继承
var fruit = new Fruit();
fruit[Symbol('level')] = 'A级';
Apple.prototype = fruit;
fruit.constructor = Apple;
var apple = new Apple('红富士');
apple[Symbol('color')] = '红色';
// 只能获取子类对象特有的属性，不能获取从父类继承的属性
console.log('apple.hasOwnProperty("name")',apple.hasOwnProperty('name')); // false
console.log('apple.hasOwnProperty("desc")',apple.hasOwnProperty('desc')); // true
console.log('Object.getOwnPropertyNames',Object.getOwnPropertyNames(apple)); // ["desc"]
console.log('Object.getOwnPropertyDescriptor(apple,"name")',Object.getOwnPropertyDescriptor(apple,'name')); // undefined
console.log('Object.getOwnPropertyDescriptor(apple,"desc")',Object.getOwnPropertyDescriptor(apple,'desc')); // Object{...}
console.log('Object.getOwnPropertySymbols(fruit)',Object.getOwnPropertySymbols(fruit)); // [Symbol(level)]
console.log('Object.getOwnPropertySymbols(apple)',Object.getOwnPropertySymbols(apple)); // [Symbol(color)]