如何在不使用javascript函数的情况下使用对象文字的属性 [英] How to use properties of an object literal without being inside a function in javascript

问题描述

我在JS中创建了一个对象文字，但是想要在不使用函数的情况下访问属性。每当我尝试时，我都没有得到任何结果，或者它返回 null 。

I created an object literal in JS, but wanna to access a property without being in a function. Whenever I try, I don't get any results or it returns null.

JS：

var settings = {
        prev: '#prev',
        next: '#next',
        slides: '#slides',
        crslContainer: '#carousel',

        //I'm trying to access the 'slides' by using 'this.slides'
        inDent: $(this.slides).find('li').outerWidth(),
        fx: 'rotate',

        myFunction: function () {
          console.log(settings.inDent); //This shows null in the console, why??
        }
    }

在上面的代码中我试图访问幻灯片使用 this.slides ，都在同一个对象中，但控制台说 null 。但是当我使用方法时， inDent：$（'＃slides'）。find（'li'）。outerWidth（），然后它就可以了。这是为什么？我假设它与使用这个关键字在函数内使用这些属性相同，显然情况并非如此。
我只是想将该对象属性的值（即字符串）传递给另一个不是函数的属性。

In the code above I'm trying to access slides by using this.slides, all inside the same object, but the console says null. But when I do the method, inDent: $('#slides').find('li').outerWidth(), then it works. Why is that? I assumed it's the same as using those properties inside a function by using this keyword, apparently it's not the case. I just wanna pass the value of that object property , i.e. a string, to another property that's not a function.

非常感谢

推荐答案

您不能在对象文字中引用正在定义的对象。也就是说，没有办法让under-construction对象的属性的值表达式引用对象本身，以便访问另一个（可能是已经定义的）属性。

You can't refer to the "object being defined" in an object literal. That is, there's no way to have the value expression for a property of the under-construction object refer to the object itself in order to access another (presumably, already-defined) property.

然而，您可以在定义对象后添加属性。

You can however add a property to the object after it's been defined.

 var obj = { a: 0 };
 obj.b = (obj.a ? 1 : 2);

或者在您的情况下：

 var settings = { ... };
 settings.inDent = ($(settings.slides).find('li').outerWidth());

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