Check out Motion Canvas[0] by Jacob from aarthificial, prolific coder and animator [1].

[0]: https://motioncanvas.io/

[1]: https://www.youtube.com/@aarthificial

I second this. The Motion Canvas codebase itself is also fascinating. Extremely well written and documented.

I've done some porting between Python and JS based on Tensorflow in the past - and I suspect the poor ergonomics in JS for math/lists would probably ruin the experience a good amount.

Perhaps something like Pyodide can bridge the gap and make it easier to bring into the browser as well.

It would probably be easier to add an 'export to js' option to Manim than to try to create an ergomic js library.

Motion Canvas might be a great fit: https://motioncanvas.io/

I wonder how the performance would be if you ran it in Pyodide.