Object Instantiation in Custom Types files have now been improved. Only those properties (of the object) that are set in client code will be initialized and instantiated in the SDK. This will prevent any property from being undefined
Whenever a Custom Type (model) is initialized in client code, an object (which assigns values to different properties/fields of this Custom Type) is optionally passed in. Whichever properties of those object are set in the client code will be initialized in the SDK. The rest of the properties of that Custom Type will be set to null