package promise_jsoo_lwt

  1. Overview
  2. Docs
package promise_jsoo_lwt
Legend:
Page
Library
Module
Module type
Parameter
Class
Class type
Source

Source file promise_lwt.ml

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
type +'a t = 'a Lwt.t

exception Promise_error of Promise.error

let of_promise js_promise =
  let lwt_promise, resolver = Lwt.wait () in
  let fulfilled value =
    Lwt.wakeup_later resolver value;
    Promise.return ()
  in
  let rejected reason =
    Lwt.wakeup_later_exn resolver (Promise_error reason);
    Promise.return ()
  in
  let (_ : unit Promise.t) = Promise.then_ ~fulfilled ~rejected js_promise in
  lwt_promise

let to_promise lwt_promise =
  Promise.make @@ fun ~resolve ~reject ->
  let reject = function
    | Promise_error e -> reject e
    | e -> reject (Obj.magic e : Promise.error)
  in
  Lwt.on_any lwt_promise resolve reject

let t_to_js (to_js : 'a -> Ojs.t) (lwt_promise : 'a t) : Ojs.t =
  Promise.t_to_js to_js (to_promise lwt_promise)

let t_of_js (of_js : Ojs.t -> 'a) (js_promise : Ojs.t) : 'a t =
  of_promise (Promise.t_of_js of_js js_promise)