面试题：（考察Object.defineProperty(obj,prop,descriptor) 的get方法）

参考链接1： javascript学习（九）对象属性的特性

参考链接2：https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty

案例1：

var person = {};
Object.defineProperty(person, "name", {
value:"Tom",
writable:false,
enumerable:false,
configurable:false
});
console.log(person.name);   //Tom
person.name = "Linda";
console.log(person.name);   //Tom

案例2：

var person = {};
Object.defineProperty(person, "name", {
value:"Tom",
writable:true,
enumerable:false,
configurable:true
});
console.log(person.name);   //Tom
person.name = "Linda";
console.log(person.name);   //Linda

图解：



案例3：官方文档解释的太好了！！！

Writable attribute

When the writable property attribute is set to false, the property is said to be “non-writable”. It cannot be reassigned.

var o = {}; // Creates a new object

Object.defineProperty(o, 'a', {
value: 37,
writable: false
});

console.log(o.a); // logs 37
o.a = 25; // No error thrown
// (it would throw in strict mode,
// even if the value had been the same)
console.log(o.a); // logs 37. The assignment didn't work.

As seen in the example, trying to write into the non-writable property doesn’t change it but doesn’t throw an error either.

以上内容作为个人学习记录使用，仅供参考，不足之处，烦请告知。