This is cool and useful, but there are still some pieces missing: For one, the data is just a javascript object, and is not pulled from a database. There is also a lot that can be automated when making a REST api. For example, Django+Django REST Framework allows you to define models and serializers and BOOM you have a browsable API, as well as all POST/GET/PUT/PATCH/DELETE REST API endpoints created. I assume there is something out there like this for node, but the author doesn't mention it.
It ends with "...we should have endpoints for updating a hero and deleting a hero, but we’ll leave that for you to implement."
I'd rather not... Can't a library set those up for me?