I like the idea of Transfer Objects within application. In my applications I use Entities (simple TO but with some additional functions like data validation, type casting, etc). Because I planned to write modern one-page-apps I decided to have Entities on the front-end as well.
That is how the idea of Gleam was born. And now I am able to write Entity once and use it on the NodeJS side and on the browser side. Every entity is automatically serialized to JSON and de-serialized on front-end to correct objects. Gleam is for now on the very early stage, it is more like "proof of concept". I still need to build some real projects based on it.