There's no way to make this synchronous w/o some sort of terrible hack. The right way is to have getAThing accept a callback function as a parameter and then call that function once thing is available.

function getAThing(callback)

{

    var db = new mongo.Db(mydatabase, server, {});



    db.open(function(err, db)

    {

        db.authenticate(myuser, mypassword, function(err, success)

        {

            if (success)

            {

                db.collection(Things, function(err, collection)

                {

                    collection.findOne({ name : bob}, function(err, thing)

                    {       

                        db.close();                    

                        callback(err, thing);

                    });

                });

            }

        });

    });

}

Node 7.6+ Update

async/await now provides a way of coding in a synchronous style when using asynchronous APIs that return promises (like the native MongoDB driver does).

Using this approach, the above method can be written as:

async function getAThing() {

    let db = await mongodb.MongoClient.connect('mongodb://server/mydatabase');

    if (await db.authenticate(myuser, mypassword)) {

        let thing = await db.collection(Things).findOne({ name: bob });

        await db.close();

        return thing;

    }

}

Which you can then call from another async function as let thing = await getAThing();.

However, it's worth noting that MongoClient provides a connection pool, so you shouldn't be opening and closing it within this method. Instead, call MongoClient.connect during your app startup and then simplify your method to:

async function getAThing() {

    return db.collection(Things).findOne({ name: bob });

}

Note that we don't call await within the method, instead directly returning the promise that's returned by findOne.