Javascript Object Literal从另一个属性引用另一个属性 [英] Javascript Object Literal referring to another property in itself from another property

问题描述

我有一个对象字面值：

var obj = {
    a : document.getElementById("ex1"),
    b : obj.a.document.getElementsByTagName("div")
};

我遇到了b属性的问题，由于某些原因它不会让这种情况发生。这可能吗？

I am having trouble with the b property, for some reason it is not letting that happen. Is this possible?

推荐答案

当定义属性 b 时， obj 尚未定义。解决该问题的一种方法是使您的属性成为一个函数，以便在调用之前不对其进行求值。

When the property b is being defined, obj is not defined yet. One way to get around that problem is to make your property a function so that it's not evaluated until called.

var obj = {
    a : document.getElementById("ex1"),
    b : function() {
      // This is not evaluated until obj.b() is called
      return obj.a.document.getElementsByTagName("div");
    }
};
obj.b();

如果你真的希望它成为一个房产，你必须分两步完成 Tomasz Nurkiewicz 显示

If you really want it to be a property, you have to do it in two steps as Tomasz Nurkiewicz shows

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