flexible query method/function for MongoDB + Express using NodeJs

I am working on an API with MongoDB+Express+Node.js. So far so good, I can query for one record by ID, I can query for a specific field, delete, add, etc.

I am looking for a method that can be called to create a generic query for mongoDB, where i will pass it a json representation of the model with 'some' data to search for. If the field is not specified in the json object, then it will only search on those fields specified.

Here is the boilerplate code I had, done, but I am very new to JavaScript and Node, and I think i need to parse or sanitize the query object before running the .find method.

Basically I want to be able to perform a query similar to how it is done in parse.com where you send an object model with the data you want to search for and you get all the results that match.

Any help would be greatly appreciated!

--This code is in my custom module--

exports.findByQuery = function(req, res) {
    var query = req.query;
    db.collection('artists', function(err, collection) {
            collection.find(query).toArray(function(err, docs) {
            res.send(docs);
        });
    });
};

--This is the routes file--

var express = require('express'),
    artist = require('./routes/artists');

var app = express();

app.configure(function () {
    app.use(express.logger('dev'));     /* 'default', 'short', 'tiny', 'dev' */
    app.use(express.bodyParser());
});

app.get('/search/', artist.findByQuery);
app.get('/artist/:id', artist.findById);
app.post('/artist', artist.addArtist);
app.put('/artist/:id', artist.updateArtist);
app.delete('/artist/:id', artist.deleteArtist);

app.listen(3000);