unsetting fields when pushing an object to array

[imri heppner]

Hi,

my problem is with mongoose setting  [ ]  for arrays without asking it to do so (in update - while pushing objects)

i am trying to do something like this:

var obj = {"field1": "some text"}
MyModel.findOneAndUpdate({"@ID": id}, {$push: {"objArray":obj}}

the simplified schema is:

var secSchema = new Schema({"field1": String, "field2":[String]});
var MyModelSchema = new Schema({"objArray":[secSchema]});

the problem is the the result object in the DB looks like:

{ "_id": ObjectId("asdasdgsdfgasf134sdf"),
 "objArray" : [ {"field1": "sometext",
               "field2": []}
            ]
}

my problem is with the 'field2'  - i don't want it to be set to [ ].

the reason is that i have many fields like that - and just once in a while they are being set - so i don't want to save it empty, it also make it difficult to use the {$exist} option later in queries.

(i saw this post but didn't manage to work it out since i am pushing pure json object and not a model.save)

is there any solution?

thanks!