JavaScript反思:获取变量的名称? [英] JavaScript Reflection: obtaining a variable's name?

问题描述

我有几个分配给同一功能的变量.属性名称"为"，因为此函数是匿名的；

I have a several variables which are assigned to the same function. The property 'name' is "" as this function is anonymous;

也不涉及函数调用，因此也没有被调用者.

There also isn't a function call involved, and as such no callee.

JS中是否有一种通过自我实现的反射算法来获取变量名称的方法?

Is there a way in JS to obtain the variable's name, through a self-implemented reflection algorithm?

例如

var x = function(){}
var myUnknownNamedVar1 = myUnknownNamedVar2 = x;

背景:

为了节省空间，成千上万的变量名称被分配给与延迟加载的树桩相同的静态"函数，它们在第一次调用时就分解为单个函数. (变量名还包含一个名称空间).

for space efficiency, thousands of variable names are assigned to the same 'static' function as a lazy-loaded stumps, which get resolved to individual functions upon the first call invocation. (The variable name also contains a namespace).

替代:

我的替代选择是使用{_name: myUnknownNamedVar1 , _fn: x}

该问题的解决方案将很有趣.一个特殊的问题是在脚本中辨别具有不同名称的变量，这些变量指向同一对象.

Solutions to this issue would be interesting. A particular issue is discerning variables with different names ,in the script, which point to the same object.

推荐答案

1.您可以尝试解析脚本的文本.

JSFiddle示例

var x = function(){}
var myUnknownNamedVar1 = myUnknownNamedVar2 = x;

var txt  = (document.currentScript && document.currentScript.textContent) ||
           (document.scripts       && document.scripts[1]
                                   && document.scripts[1].textContent);
var arr  = txt.match(/var\s*(.*)\s*=\s*x\b/);
arr[1]   = arr[1].replace(/\s+$/,"");
var vars = arr[1].split(/\s*=\s*/);

// vars: ["myUnknownNamedVar1", "myUnknownNamedVar2"]

---

2.您可以尝试比较值

JSFiddle示例

var x = function(){}
var myUnknownNamedVar1 = myUnknownNamedVar2 = x;

var vars = [];
for (var prop in window){
    if (window[prop] == x)
      vars.push(prop);
}

// vars: ["x", "myUnknownNamedVar1", "myUnknownNamedVar2"]

---

注意:这两种方法都需要改进(例如，递归，更好/更多的匹配模式).第二个仅查看全局变量，而闭包中的某些变量可能不会公开给全局命名空间.另外，还有一些对象.

---

Note: Both methods will need refining (eg recursion, better/more match patterns). The second one only looks at global variables, whereas some variables in closures may not be exposed to the global namespace. Also, there are objects of objects.

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