Google Chrome Object.defineProperty中的错误行为？ [英] Wrong behaviour in Google Chrome Object.defineProperty?

问题描述

  var Player = function（高度）{
 var _height = height; 
 
 Object.defineProperty（this，'height'，{
 enumerable：false 
，可配置：true 
，可写：false 
，get：function （）{return _height;} 
，set：function（val）{_ height = val;} 
}）; 
 
  

var myPlayer = new Player（10）;

即使defineProperty选项的可写属性设置为false，我也会得到以下错误：

无效的属性。一个属性不能同时拥有访问器，并且可写或具有值，＃< Object>

当然，$ c> writable 设置为true，但是如果我删除可写行，错误消失。

我做错了什么，或者这是一个错误？这发生在谷歌浏览器版本30.0.1599.66上。

解决方案 Mozilla MDN for Object.defineProperty 澄清这：

对象中的属性描述符有两种主要特征：数据描述符和访问符描述符。数据描述符是一个具有值的属性，该值可能是可写的，也可能不是可写的。访问器描述符是由getter-setter函数对描述的属性。描述符必须是这两种口味之一;它不能同时存在。

这意味着您可以使用以下任何一种：

• 可写和值


• get 和 set

但是你不能使用它们的任何组合。在你的例子中，你指定了可写属性，这意味着它是一个数据描述符，它不允许 get 和 set 属性。

I am trying to create an object with setters and getters, and this is my code:

var Player = function(height){
    var _height = height;

    Object.defineProperty(this, 'height', {
      enumerable: false
    , configurable: true
    , writable: false
    , get: function(){return _height;}
    , set: function(val){_height = val;}
    });
}

var myPlayer = new Player(10);

Even though the writable property of the defineProperty options is set to false, I get the following error:

Invalid property. A property cannot both have accessors and be writable or have a value, #<Object>

The same is happening when the writable is set to true of course, but the error disappears if I remove the writable line.

Am I doing something wrong, or is this a bug? This is happening on Google Chrome, Version 30.0.1599.66

解决方案

The Mozilla MDN for Object.defineProperty clarifies this:

Property descriptors present in objects come in two main flavors: data descriptors and accessor descriptors. A data descriptor is a property that has a value, which may or may not be writable. An accessor descriptor is a property described by a getter-setter pair of functions. A descriptor must be one of these two flavors; it cannot be both.

This means, that you can use either one of those:

• writable and value
• get and set

But you cannot use any combination of them. In your example, you specify the writable attribute, which means that it is a data descriptor, which disallows get and set attributes.

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