Deep Copy walk with forced async completion before return

gistfile1.js

var http = require('http');
var request = require('request');

var samplePayload = {
        "key1":{
            "key1.1": {
                "key1.1.1": ["val1.1.1.1", "val1.1.1.2", "val1.1.1.3", "val1.1.1.4"]
            },
            "key1.2": ["val1.2.1" ,"val1.2.2"]
        },
        "key2":"val2"
    }

function attemptClose(response, callStack, parentResult){
    if(callStack.length==0){
        response.end(JSON.stringify(parentResult, undefined, 4));
    }
}

function processObjWithRef(obj, result, callStack, res, parentResult){
    if(obj==null || typeof obj != 'object'){
        //nothing really to do here - you're going to lose the reference to result if you try an assignment
    }
    if(obj instanceof Array) {
        for(var i=0; i<obj.length; i++){
            result.push();
            processObjWithRef(obj[i], result[i], callStack, res, parentResult);
        }
    }    
    if(obj instanceof Object){
        for(var l in obj){
            (function(){
                var k = l;
                if(obj[k]==null || typeof obj[k] != 'object'){
                    callStack.push("some_value");
                    request({ uri:"http://www.craigslist.com"}, function (error, response, body) {
                        var snippet = body.substring(0, 50)+"...";
                        result[k] = snippet;
                        callStack.pop();
                        attemptClose(res, callStack, parentResult);
                    });
                }else if(obj[k] instanceof Array) {
                    result[k] = [];
                    processObjWithRef(obj[k], result[k], callStack, res, parentResult);
                }else if(obj[k] instanceof Object){
                    result[k] = {};
                    processObjWithRef(obj[k], result[k], callStack, res, parentResult);
                }
            })();
        }
    }
}

function processRequest(req, res){
    var callStack = [];
    var myNewObj = {};
    processObjWithRef(samplePayload, myNewObj, callStack, res, myNewObj);
    attemptClose(res, callStack, myNewObj);
}

var server = http.createServer(processRequest);
server.listen(8080);