I wanted to figure out the simplest, most lightweight abstraction, that unifies static site generation and web server for both HTML, JSON, etc. What I arrived at is ~700 lines of TypeScript:

https://mastrojs.github.io/

In a docs-first approach, before building the framework above, I actually first wrote the following guide where you build a static blog, and implement a to-do list app: once with plain JavaScript, then reactively. Finally, you run a server with a REST API, and learn about caching and different architectures:

https://mastrojs.github.io/guide/