promise_to_Deferred.t or: async_js wait on a JS promise

Learning
1

short description

I am looking for the inverse of: async_js/main.ml at master · janestreet/async_js · GitHub

let promise_of_deferred d =
  let promise = Js.Unsafe.global##._Promise in
  new%js promise
    (Js.wrap_callback (fun resolve (_reject : 'a) -> don't_wait_for (d >>| resolve)))
;;

context

I have a piece of JS code that is an async function

let js_code =
{|
  (async function(...) { ... } )
|}

I compile this function with Js.Unsafe.js_expr js_code, and when I call it from OCaml land, I get a promise back.

Question: how do I want on this promise from async_js Deferred.t ?

Thanks!