I won’t wax long and poetic here since I’ve already posted the experiment that has all the details.
TL;DR: there are still only ~90-ish in the WebR WASM “CRAN”, but more are absolutely on the way, including the capability to build your own CRAN and dev packages via Docker and host your own WebR WASM pkg repo.
@timelyportfolio created an experimental method to install built base R packages from R Universe, and I enhanced that method in another, recent experiment, but that’s a bit wonky, and you have to do some leg work to figure out if a package can be installed and then do a bunch of manual work (though that Observable notebook will save you time).
The aforelinked new experiment shows how to use Pyodide side-by-side with WebR. While this one doesn’t have them sharing data or emscripten filesystems yet, we’ll get there! This puts SCADS of Python packages at your fingertips to fill in the gap while we wait for more R to arrive.