Bowler Studio was sort of revelatory for me, because it gave me the ability to model a functional part and immediately test it. The physics engine obviously isn't going to be the most accurate of all time, but for a lot stuff that hobbyists do it can be useful, and being able to play with servos and motors really does open a lot of possibilities to avoid wasting time and prints.

I've actually played with ShapeScript but I admit that I didn't do anything terribly crazy with it.

Yeah I've only dabbled with it myself. Again it was part of this process of me orienting myself towards "thinking in 3D" and I'm really grateful to much more 3D-literate developers than me that we have so many choices.

CascadeStudio is another one:

https://github.com/zalo/CascadeStudio

This is a browser-based JS CAD thing built around an Emscripten cross-compilation of OpenCascade -- the fact that it works at all was revelatory to me about the capability of Emscripten, which had passed me by a little.

So this is JS code-CAD in a bRep world.

CascadeStudio is new to me - this is really cool. Thank you for linking it.

I have found there is another OpenCascade-based JS CAD -- RepliCAD -- which is significantly more developed.

https://replicad.xyz

And it's even embeddable, which is super-cool:

https://sample-app.replicad.xyz