You guys feel free to keep being JS-phobic but please don't describe setting up an ECMAScript runtime environment scarily complicated. It's apt install node npm notably on Ubuntu/Debian. That's it.
Besides, there are Bun and Deno now which are evidently faster runtime than Node.
If you have a problem with the language itself, please criticise at it, not something made from it. In fact, being a programmatic schematic file, a script rather than a compiled language makes more sense because a script evolves faster in development while sacrificing performance. Performance isn't top priority.
And you said it's object-oriented? Which part of this piece of code in their tutorial looks OO to you?
https://fluidcad.io/docs/guides/sketching/introduction
circle(50, "xy") // circle on the XY plane
rect(100, 60, "front") // rectangle on the front plane
line([0, 0], [100, 50], "xz") // line on the XZ plane
slot(80, 20, "xy") // slot on the XY plane
arc(50, 0, 90, "front") // arc on the front plane