读取对象属性
设置属性对象上没有该属性时会从原型上检测属性描述符
```
const foo = {}
Object.defineProperty(foo, 'name', {
writable: false,
value: 'John'
})
const bar = Object.create(foo)
bar.name = 'Arya'
console.log(bar.name) // => John
```
const foo = {}
Object.defineProperty(foo, 'name', {
writable: false,
value: 'John'
})
const bar = Object.create(foo)
bar.name = 'Arya'
console.log(bar.name) // => John
```