Async_js.DebugSourceOutput a Sexp.t value to the console, e.g. via the message extensions:
log_s [%message "An example" (of_using:Ppx_message.t)]log_s_as_string logs the sexp as a string instead of as a JavaScript object, so that it appears fully expanded in the console.
Convert a sexp expression into a JavaScript object. This can be used to output OCaml values to the console.