Delete a key from a MongoDB document using Mongoose

In early versions, you would have needed to drop down the node-mongodb-native driver. Each model has a collection object that contains all the methods that node-mongodb-native offers. So you can do the action in question by this:

User.collection.update({_id: user._id}, {$unset: {field: 1 }});

Since version 2.0 you can do:

User.update({_id: user._id}, {$unset: {field: 1 }}, callback);

And since version 2.4, if you have an instance of a model already you can do:

doc.field = undefined;
doc.save(callback);

You'll want to do this:

User.findOne({}, function(err, user){
  user.key_to_delete = undefined;
  user.save();
});

I use mongoose and using any of the above functions did me the requirement. The function compiles error free but the field would still remain.

user.set('key_to_delete', undefined, {strict: false} );

did the trick for me.

At mongo syntax to delete some key you need do following:

{ $unset : { field : 1} }

Seems at Mongoose the same.

Edit

Check this example.