Using variables in MongoDB update statement

Question

I am trying to use a variable as the field name in an update statement and it is not working at all, any suggestions?

for example:

COLLECTIONNAME.update(
    { _id: this._id },
    { $set: { VARIABLE1 : VARIABLE2 } }
);

actual code:

 'blur .editable' : function () {
      var target = event.currentTarget.value;
      var field = event.currentTarget.name;
      field = ' " ' + field + ' " ';
      Hostings.update( { _id: this._id },{ $set: { field : target } } );
    }

Answer 1

As per L. Norman's comment, I find using the [] for the field value works instead

collection = "my_collection"
db.getCollection(collection).find({}).forEach(function(doc) {
    var new_field = "new_field";
    var new_value = "new_value";

    db.getCollection(collection).update({_id: doc._id}, 
        {$set: {[new_field] : new_value}}) 
})