$unset support in mongo node driver?

[Eric Fossas]

If I want to delete a key from a document using the mongo shell, I would use the following command:

db.collection.update({_id:"some_id"},{$unset:{"the.nested.key.to.delete":""}});

Is this supported in the mongo node driver? It doesn't seem to work. I tried:

db.collection('my_collection').update({_id:"some_id"},{$unset:{"the.nested.key.to.delete":""}},function(err,result) {

    // etc.

});

But that didn't work. I know I could find/retrieve the document, delete the key, then update it... but I'm not a fan of that approach. So is $unset supported, or is there another approach I should be using that I haven't thought of?

[Kevin Adistambha]

Hi Eric,

Using the Node MongoDB driver version 2.2.25, this works for me:

> db.test.find()
{
  "_id": 0,
  "a": 1,
  "b": 2,
  "c": 3
}

var MongoClient = require('mongodb').MongoClient;

MongoClient.connect('mongodb://localhost/test', function(err, db) {
    db.collection('test').update({'_id': 0}, {'$unset': {'a': ''}}, function(err, res) {
        db.close();
    });
});

> db.test.find()
{
  "_id": 0,
  "b": 2,
  "c": 3
}

You might be missing quotes on the fields such as _id and $unset.

If it still doesn’t work for you, could you post:

• Your MongoDB and your OS version
• Your Node driver version
• The complete code that you tried
• Any error message that you see in mongod log, within node, etc.

Best regards,
Kevin

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