JavaScript 获取变量名

发布于 2024-09-30 20:43:33 字数 843 浏览 3 评论 0原文

这是我的第一篇文章。

我正在尝试使用 javascript 进行一些基本的元编程，我想知道是否有一种方法可以获取特定对象的 id 并使用该 id 访问变量名称，或者简单地获取某个对象的变量名称特定对象。我想重新创建一种情况，您首先在网页中创建每个 html，然后附加到与特定类（例如类 Person）关联的一些 html 标记事件。例如：假设下一个代码：

var someFunction = function(someText){alert(someText);}
function SomeClassFunction(){
     this.aClassFunction = someFunction;
}

var aVariableName = new SomeClassFunction();

在 HTML 代码中假设我有下一段代码。

<html>
  <head>
    <title></title>
  </head>
  <body>
    <div onclick="aVariableName.aClassFunction('Some text to show in alert');">
    </div>
  </body>
</html>

然后，您可能会注意到 onclick 事件使用我之前创建的 aVariableName，但因为我首先创建变量的名称，然后在代码中附加该名称，所以我知道 aVariableName 是该对象的名称。我想要做或实现的是在 html 中创建上面的文本，而不知道特定对象的变量名称。我在网上冲浪，但不幸的是我没有找到任何相关信息。

原文

This is my first post.

I'm trying to do some basic meta-programming with javascript, and I was wondering if there is a way of get the id of a particular object and with that id, access to the variable name, or get simply the variable name of a particular object. I wanna recreate a situation in which you first create every single html in a web page, and append to some of the html tags events associated to a particular class -example class Person-. for example: Supposed the next code:

var someFunction = function(someText){alert(someText);}
function SomeClassFunction(){
     this.aClassFunction = someFunction;
}

var aVariableName = new SomeClassFunction();

and in the HTML code suppose I have the next piece of code.

<html>
  <head>
    <title></title>
  </head>
  <body>
    <div onclick="aVariableName.aClassFunction('Some text to show in alert');">
    </div>
  </body>
</html>

Then, as you may notice the onclick event uses the aVariableName I created before, but because I first create the name of the variable and then append the name in the code cause I knew aVariableName was the name of that object. What I wanna do or implement is to create the text above in html without know the variable name of an specific object. I have surfed on the net but, unfortunately I haven't found anything about it.

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染年凉城似染瑾 2024-10-07 20:43:33

我不知道如何从代码本身获取变量的名称，而不需要做大量的解析工作，这会变得混乱，我会为此开枪打死某人。

var someValue;
var foo = function() { someValue; }
alert((foo + '')); // this is now a string, use substr to extract variable name

您知道可以在 javascript someElement.onclick = someFunction 中设置类似的事件，因此如果您所做的只是设置事件处理程序，则实际上不需要知道变量的名称。

i dont know how to get the name of a variable from the code its self without doing a whole load of work parsing stuff, which will get messy, and i'd shoot someone for this.

var someValue;
var foo = function() { someValue; }
alert((foo + '')); // this is now a string, use substr to extract variable name

You know you can set events like this in javascript someElement.onclick = someFunction so you dont really need to know the name of the variable if all you're doing is setting an event handler.

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电影里的梦 2024-10-07 20:43:33

一般来说，不可以——您也无法获取特定变量的名称或其“id”。

如果你真的愿意，也许可以用异常和堆栈跟踪来做坏事来获取这些信息……但我不知道该怎么做。

编辑：我假设“变量 ID”是指“该变量引用的对象的唯一标识符”，就像 Python 的 id 内置函数一样：

>>> x = {}
>>> y = z = {}
>>> (id(x), id(y), id(z))
(123, 567, 567)

In general, no — you can't get the name of a particular variable or its "id" either.

If you really want to, it may be possible to do Bad Things with exceptions and stack traces to get that information… But I don't know off the top of my head how to do that.

Edit: I assume that, by “variable ID”, you mean “a unique identifier for the object referenced by that variable”, like Python's id builtin:

>>> x = {}
>>> y = z = {}
>>> (id(x), id(y), id(z))
(123, 567, 567)

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习惯成性 2024-10-07 20:43:33

我不能 100% 确定我正确理解您关于元编程的问题，但通常您会将事件处理程序附加到 DOM 元素的单击事件，然后您可以检查处理程序中元素的属性。

JavaScript 中有一些功能可以促进元编程：eval 可以让您解释任意代码，因此您可以构建一串代码并对其进行评估。安全问题有很多。您还可以通过索引或名称访问对象的属性，例如

aVariableName.aClassFunction

与

aVariableName["aClassFunction"]

希望有帮助。

I'm not 100% sure that I understand your question correctly in regards to meta-programming, but typically you would attach an event handler to the click event of the DOM element, then you can examine properties of the element within the handler.

There are a couple things in JavaScript that facilitate meta-programming: eval will let you interpret arbitrary code, so you can build a string of code and eval it. The security concerns are numerous. You can also access properties of an object by index or by name, e.g.