Google Closure编译器-如何为变量创建外部变量(变量名称不能像在Eval中一样更改) [英] Google Closure Compiler - How to create an Extern for a variable (variable name can't change as it is in an Eval)

问题描述

我在"SIMPLE_OPTIMIZATIONS"模式下使用Google Closure编译器. JavaScript使用"Eval"语句，并将变量"_u"嵌入字符串中.当Google Closure Compiler对代码进行混淆处理时，变量名称更改为"a"，并且我收到一个错误，即控制台中未定义"_u".我的理解是，Extern可以解决此问题，但是我不确定如何编写它.有想法吗?

I am using Google Closure Compiler in "SIMPLE_OPTIMIZATIONS" mode. The JavaScript uses an "Eval" statement with the variable "_u" embedded in the string. When Google Closure Compiler obfuscates the code, the variable name is changed to "a" and I get an error that "_u" is not defined in the console. My understanding is that an Extern will solve this problem, but I'm not sure how to write it. Thoughts?

代码段:

var FuncName = (function(){

  var ht=escape(_w.location.href)

  function _fC(_u){
    _aT=_sp+',\\/,\\.,-,_,'+_rp+',%2F,%2E,%2D,%5F';
    _aA=_aT.split(',');
    for(i=0;i<5;i++){
      eval('_u=_u.replace(/'+_aA[i]+'/g,_aA[i+5])')
    }
    return _u
  };

  return {
  O_LC:function(){ 
    _w.open('https://someurl?referer='+_fC(_ht))
  }
};
})();

在Google Closure Compiler修改代码后:

After Google Closure Compiler modifies the code:

var FuncName = function() {
  function a(a) {
    _aT = _sp + ",\\/,\\.,-,_," + _rp + ",%2F,%2E,%2D,%5F";
    _aA = _aT.split(",");
    for (i = 0;5 > i;i++) {
      eval("_u=_u.replace(/" + _aA[i] + "/g,_aA[i+5])");
    }
    return a;
  }
  escape(_w.location.href);
  return {O_LC:function() {
    _w.open("https://someurl?referer=" + a(_ht));
  }};
}();

推荐答案

您只能阻止使用externs重命名全局变量或属性.当地人将始终被重命名.您可以通过多种方法修改代码以解决此问题，包括使用函数构造函数:

You can only prevent renaming of global variables or properties with externs. Locals will always be renamed. You can modify the code in a number of ways to fix this, including using a function constructor:

new Function("_u", "... function body ...")

但是我会重写代码以避免使用eval构造正则表达式.这将起作用:

But I would rewrite the code to avoid using eval to construct the regex. This would work:

_u=_u.replace(new RegExp(_aA[i], "g"), _aA[i+5]);

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在Javascript正则表达式中使用的转义字符串

有关Closure Compiler限制的一般文档在这里:

General documentation regarding the Closure Compiler limitations are here:

https://developers.google.com/closure/compiler/docs/limitations

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