title: MongoDB on Node.js doesn't work, it returns undefined
body: <p>In the following code:</p>
  
  <pre><code>var MongoClient = require('mongodb').MongoClient;
  MongoClient.connect('mongodb://localhost:27017/db_name', function(err, db){
      if (err) throw err;
  
      var collection = db.collection('col_name');
      console.log(collection.find().toArray(function(err, items){}));
  
  });
  </code></pre>
  
  <p>When I run the above, it doesn't return any results and instead returns <code>undefined</code>. What am I missing?</p>
  
  <p>Also, in order to confirm there exist some collections on the db, which there are, I tried to add <code>console.log(db.getCollectionNames());</code>, but it looks like it has no such method in Node.js driver. So is it still possible to confirm the existence of collections? (Anyway I just want to use it as debug in these situations - usually I don't need the method though).</p>
  
  <p>Thanks. </p>