Last I checked, WASM support isn't quite there, yet, basically. I haven't checked in a little while, though.
emscripten-forge is a package repo of conda packages for `linux-64 emscripten-32 emscripten-wasm32 osx-arm64 noarch` built with rattler-build and hosted with quetz: https://repo.mamba.pm/emscripten-forge
Evcxr is a rust kernel for jupyter; but jupyter-xeus is the new (cpp) way to write jupyterlite kernels like xeus-, xeus-sqlite, xeus-lua, xeus-javascript, xeus-javascript
[1]: evcxr_jupyter > "jupyter lite and conda-forge feedstock(s)" https://github.com/evcxr/evcxr/issues/399
[2]: emscripten-forge > "recipes_emscripten/rust and evxcr_jupyter kernel" https://github.com/emscripten-forge/recipes/issues/1983