 (* compiles *)
let b = f [%obj {height = 3 ; width  = 32; unused = 3 }] (* compiles *)
```

---

## FFI examples (http server using Node.js)

- `Test_http_server`

```ocaml
let port = 3000
let hostname = "127.0.0.1"
let create_server http  =
  let server = http##createServer begin fun [@bs] req  resp  ->
      resp##statusCode #= 200;
      resp##setHeader "Content-Type" "text/plain";
      resp##end_ "Hello world\n"
    end
  in
  server##listen port hostname  begin fun [@bs] () ->
    Js.log ("Server run