Use cliapp

make.R

 library(sass)
 library(fs)
 library(purrr)
+library(cliapp)
 
 render_sass <- function(file, output = NULL, outdir = "rsthemes") {
   if (is.null(output)) {
     path_ext(output) <- "rstheme"
   }
   output <- path(outdir, output)
+  cli_alert_success("{path {path_file(file)}}")
   sass(sass_file(paste(file)), output = output)
 }
 
 dir_create("rsthemes")
 
+cli_alert_info("Compiling themes...")
 dir_ls(regexp = "^[^_].+\\.scss") %>%
   walk(render_sass)
 
 cp_to_rstudio <- function(file) {
+  cli_alert("{path {path_file(file)}}")
   file_copy(
     file, 
     path_home_r(".R", "rstudio", "themes", path_file(file)),
   )
 }
 
+cli_alert_info('Installing themes to {path {path_home_r(".R", "rstudio", "themes")}}')
 dir_ls("rsthemes", regexp = "\\.rstheme") %>%
   walk(cp_to_rstudio)