javascript - 为什么 bound_function.toString() 不返回原始源代码？

Question

例子:

function f(a){ return a }
var g = f.bind(null);
g.toString() // chrome:  function () { [native code] }
             // firefox: function bound f() { [native code] }

g.toString() 没有返回原始源代码是否有一些微妙的原因？

当然，我可以通过重写 Function.prototype.bind 轻松地“修复”它，但我的问题是:我是否在做一些愚蠢的事情，比如用它打开一些安全漏洞？

var o_bind = Function.prototype.bind;
Function.prototype.bind = function(){
        var f = o_bind.apply(this, arguments);
        f.orig_func = this;
        return f;
}
function fsrc(f){
        return f.orig_func ?
                String(f.orig_func).replace(/^function/, '$& bound') :
                String(f);
}

Answer 1

The spec says about Function.protoype.toString (强调我的):

If func is a Bound Function exotic object, then
Return an implementation-dependent String source code representation of func. The representation must conform to the rules below. It is implementation dependent whether the representation includes bound function information or information about the target function.

换句话说，环境可以自由包含或不包含原始函数的源。

---

am I doing something stupid like opening some security hole with this?

考虑到 toString 返回“普通”用户定义函数的函数源代码，可能不会。