Jupyterlite-xeus compiles jupyterlab to WASM.

jupyterlite-xeus builds jupyterlite, Jupyter xeus kernels, and the specified dependencies to WASM with packages from conda-forge or emscripten-forge.

The jupyterlite-xeus docs say that the xeus-r kernel is already supported: https://github.com/jupyterlite/xeus

jupyter-xeus/xeus-r: https://github.com/jupyter-xeus/xeus-r

emscripten-forge/recipes already has packages for "r-askpass, r-base, r-base64enc, r-bit, r-bit64, r-cachem, r-cli, r-colorspace, r-data.table, r-digest, r-dplyr, r-ellipsis, r-fansi, r-farver, r-fastmap, r-ggrepel, r-glue, r-haven, r-hexbin, r-htmltools, r-isoband, r-jsonlite, r-later, r-lattice, r-lazyeval, r-magrittr, r-mass, r-matrix, r-mgcv, r-mime, r-nlme, r-plyr, r-promises, r-purrr, r-rcpp, r-readr, r-rlang, r-sp, r-stringi, r-sys, r-tibble, r-tidyr, r-tzdb, r-utf8, r-vctrs, r-vroom, r-xfun, r-yaml" in WASM: https://github.com/emscripten-forge/recipes/tree/main/recipe...

It looks like xeus-r and webr both compile with emscripten; for which there's emscripten-forge which is like conda-forge but for browser WASM.