title: variable with mongodb dotnotation
body: <p>I want to increase a field inside an object object inside a mongodb document by 1.</p>
  
  <pre><code>  var stuffID = 5
    collection.update({
      "id": id,
    },
    {
      '$inc': {
        'stuff.stuffID': 1
      }
    },
    function(err, doc) {
      res.end('done');
    });
  </code></pre>
  
  <p>I need to make that stuffID a variable. Any way to do that? Thanks.</p>
  
  <p>This is using node-mongodb-native if that helps.</p>
  
  <p>If you're voting to close can you explain what it is you don't understand?</p>