Use websockets with Control.Reactive in Purescript

Main.purs.hs

module Main where

import Control.Monad.Eff
import Control.Reactive
import Debug.Trace
import Prelude

foreign import websocket
  "function websocket(url) {\
  \    return function(outgoing) {\
  \        return function(){\
  \            var conn = new WebSocket(url);\
  \            var buff = [];\
  \            var incoming = _ps.Control_Reactive.newRVar(\"\")();\
  \            conn.onopen = function(e) {\
  \                buff.forEach(function(msg){conn.send(msg)});\
  \                buff=[];\
  \            };\
  \            outgoing.subscribe(function(msg){\
  \                conn.readyState === \"OPEN\" ? conn.send(msg) : buff.push(msg);\
  \            });\
  \            conn.onmessage = function(e){\
  \                incoming.update(e.data);\
  \            };\
  \            return incoming;\
  \        };\
  \      };\
  \}" :: forall eff. String -> RVar String -> Eff (reactive :: Reactive | eff) (RVar String)


currentTrack = "{\"jsonrpc\": \"2.0\", \"id\": 1, \"method\": \"core.playback.get_current_track\"}"

main = do
  outgoing <- newRVar ""
  incoming <- websocket "ws://192.168.1.129:6680/mopidy/ws/" outgoing
  subscribe incoming trace

  writeRVar outgoing currentTrack