To your second point, the JSON spec allows `null` but not `undefined`, so most js serializers (all?) don't send (or throw an exception) for any `undefined` from

To your second point, the JSON spec allows `null` but not `undefined`, so most js serializers (all?) don't send (or throw an exception) for any `undefined` from any object you attempt to send. To delete a property, you would send the entire surrounding object. Or you can simply define your data-layer without transient key/values. It's certainly not a necessary feature to have.