export ocaml function to call from js

main.ml

let global_nctx = ref Kernel.Context.empty
let global_ectx = ref Kernel.Context.empty

let js_run_repl str =
  match String.(compare str "quit") with
  | 0 -> "bye"
  | _ ->
  match String.(compare str "reset") with
  | 0 ->
    global_nctx := Kernel.Context.empty;
    global_ectx := Kernel.Context.empty;
    "reset success"
  | _ ->
    try
      let stmts, naming_ctx =
        str
        |> Parsing.Parser.parse_string
        |> Fun.flip Ast_conv.parser_to_internal_stmts
          !global_nctx
      in
      try
        let stmts' , ctx' =
          stmts
          |> Fun.flip Kernel.Eval_statements.eval_stmts !global_ectx
        in
        let res = stmts'
        |> Pretty_print.unparse_internal_expr naming_ctx in
        global_nctx := naming_ctx;
        global_ectx := ctx';
        res
      with exc ->
        Error_reporting.fmt_eval_err_str naming_ctx exc
    with exc ->
      Error_reporting.fmt_parse_err_str exc
      
let () =
  Js.export_all
  (object%js
    method js_run_repl = Js.wrap_callback js_run_repl
  end)

node.out

Welcome to Node.js v15.4.0.
Type ".help" for more information.
> var mod = require('./main.bc');
undefined
> mod.js_run("constant P : Prop");
MlBytes { t: 0, c: 'bye', l: 3 }
> mod.js_run_repl
undefined
>