MongoDB Time conversion - node.js

Question

I have a MongoDB collection that I am querying based on a time frame and address number. If the query is successful, then the server will return a CSV file with a number of attributes stored in each query entry. This part is working fine.
The problem is that one of the attributes in my CSV file is the timestamp. I'd like it to return the local date time (ie. "Time":"2014-02-09T06:00:02.000Z")... however the CSV file is returning the date object in milliseconds (ie. "Time":1392040717774). Is there an easy way to transform the query entry before it's written to the CSV file to a local date string? Here's my code snippet:
var JSONStream = require('JSONStream');
var httpserver = http.createServer(function(req, res) {
var pathname = url.parse(req.url).pathname;
if (pathname=="/DownloadUCData") {
var requestData = '';
req.on('data', function (data) {
requestData += data;
});
req.on('end', function () {
var json = JSON.parse(requestData);
var st = new Date(json.startDate);
var et = new Date(json.endDate);
st.setHours(st.getHours()-4); //compensate for GMT offset
et.setHours(et.getHours()-4);
st=st.getTime();
et=et.getTime();
var proj=JSON.parse('{"state":1, "temperature":1, "mode":1, "speed":1, "time":1}');
var cursor = userControlCollection.find({"addr": json.addr.toString(), "time": {$gte:st, $lte:et}}, proj);
var dbstream = cursor.stream();
var tempname = json.type+".csv";
var wstream = fs.createWriteStream(tempname);
wstream.on('error', function(e){console.error(e);});
dbstream.on("end", function() {
wstream.end();
console.log("write end");
res.writeHead(200, {"Content-Type": "application/json"});
res.write(JSON.stringify({fname:tempname}));
res.end();
return;
});
var jsonToStrings = JSONStream.stringify(false);
dbstream.pipe(jsonToStrings).pipe(wstream);
});
}

Answer 1

So, I figured out one way to solve this problem (although there may be others). Basically, I had to add a transformation into the piping system to convert the .getTime() data into a new Date() object. Here's the code snippet which seemed to resolve the issue:
var Transform = require('stream').Transform;
var parser = new Transform({objectMode: true});
parser._transform = function(data, encoding, done) {
if(data.time) data.time = new Date(data.time);
this.push(data);
done();
};
var jsonToStrings = JSONStream.stringify(false);
dbstream.pipe(parser).pipe(jsonToStrings).pipe(wstream);