I am trying to query my database for a matching '_id' but the results are coming back null, but in the mongodb shell it is coming back with the correct results. Here is the code I am using.

var collection = new mongodb.Collection(client, 'products');
collection.findOne({ _id : 50738ebbe3d87c6beaddb6f2 }, function(err, result){
  res.send(result);
  console.log(result);
});

I've also tried using,

"ObjectId('50738ebbe3d87c6beaddb6f2')"

but that also come back 'null'.

The correct syntax is:

collection.findOne({ _id : new mongodb.ObjectID('50738ebbe3d87c6beaddb6f2') }, 
  function(err, result){
    res.send(result);
    console.log(result);
  }
);