JavaScript的：数组文本内访问自己的对象属性 [英] JavaScript: Access own Object Property inside Array Literal

问题描述

，访问自己的对象的属性似乎不工作：

Given an Array Literal inside a JavaScript Object, accessing its own object's properties does not seem to work:

 var closure =  {

         myPic : document.getElementById('pic1'),
         picArray: [this.myPic]
 }    

 alert(closure.picArray[0]); // alerts [undefined]

而通过访问其他JavaScript对象声明数组项目似乎工作

Whereas declaring an Array Item by accessing an other JavaScript Object seem to work

 ​var closure1 = {
 ​    
 ​     myPic : document.getElementById('pic1')
 ​}
 ​    
 ​var closure2 =  {
 ​  
 ​        picArray: [closure1.myPic]
 ​}    
 ​    
 ​alert(closure2.picArray[0]); // alerts [object HTMLDivElement]

例：
http://jsfiddle.net/5pmDG/

推荐答案

的这个值不会喜欢这项工作，它是指通过实际执行上下文确定的值，而不是你的对象文本。

The this value will not work like that, it refers to a value determined by the actual execution context, not to your object literal.

如果你声明的对象实例的函数成员，你可以得到期望的结果：

If you declare a function member of your object for example, you could get the desired result:

var closure =  {
  myPic: document.getElementById('pic1'),
  getPicArray: function () {
    return [this.myPic];
  }
};
//...
closure.getPicArray();

由于这个值时， getPicArray 函数中，会参考你的关闭对象。

Since the this value, inside the getPicArray function, will refer to your closure object.

请参阅这个答案另一个问题，在这里我解释的行为在这个关键字。

See this answer to another question, where I explain the behavior of the this keyword.

编辑：在回答您的意见，因为我提供的例子中， getPicArray 方法将生成一个新的数组对象的每个一次调用，因为你是想存储阵列，并进行更改，我建议你这样的事情，你的构造对象分为两步：

In response to your comment, in the example that I've provided, the getPicArray method will generate a new Array object each time it is invoked, and since you are wanting to store the array and make changes to it, I would recommend you something like this, construct your object in two steps:

var closure =  {
  myPic: document.getElementById('pic1')
};
closure.picArray = [closure.myPic];

然后就可以修改 closure.picArray 成员没有任何问题。

这篇关于JavaScript的：数组文本内访问自己的对象属性的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！