get all values of the closure in node.js or V8

Question

For example, if we assume the following code:

var f = function() { return 'hello world' };
var x = 10;
var y = 314;

var g = function() {
    var buf = [], xx = x;
    while (xx--)
        buf.append(f() + ' ');
    return buf.join('');
}

I can get the actual "code" as a string of g with g.toString(). However, this does not (obviously) get f and x—members of the closure of g (sorry if I'm not quite using these terms correctly.)

Is there some way to query a function for what its closure contains? Ideally I could get an object like:

{ 'f' : f, 'x': x } // note that `y` is not here

If I have to drop into C++ for special interactions with V8, that's okay—although somehow doing this in pure JavaScript would be best.

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I know that this is a bit of an odd question—but I do have a legitimate reason for wanting this!

Answer 1

I found this discussion of V8 closure implementations enlightening. It sounds like the C++ object you're looking for is a Context.