wbsocket.fs

    let inline websocket<'Data> =
        FunctionComponent.Of(fun (props: {| url : string; retryTimeSpan : TimeSpan; onConnected: bool -> unit; onMessage: 'Data -> unit |}) ->
            let mutable currentlyConnected = false
            let mutable wasAlreadyConnected = false
            let connected = Hooks.useState false
            let mutable webservice = null

            let connect() =
                if currentlyConnected then () else
                let ws = WebSocket.Create(props.url)

                ws.onclose <- unbox (fun _ ->
                    match ws.readyState with
                    | WebSocketState.CLOSED ->
                        currentlyConnected <- false
                        connected.update (fun _ -> currentlyConnected)
                    | _ -> ()
                )

                ws.onmessage <- unbox (fun (msg: MessageEvent) ->
                    let msg' = msg.data |> string
                    if not (System.String.IsNullOrWhiteSpace msg') then
                        let decoded = ServerCode.JSON.ofJson<'Data> msg'
                        props.onMessage decoded
                        unbox None
                )

                ws.onopen <- unbox (fun _ ->
                    match ws.readyState with
                    | WebSocketState.OPEN ->
                        props.onConnected wasAlreadyConnected
                        currentlyConnected <- true
                        wasAlreadyConnected <- true
                        connected.update (fun _ -> currentlyConnected)
                    | _ -> ()
                )

                webservice <- ws

            let register() =
                let retry = setInterval (fun _ -> connect()) (int props.retryTimeSpan.TotalMilliseconds)
                connect()

                { new IDisposable with
                    member __.Dispose() =
                        clearInterval(retry)
                        if not (isNull webservice) then
                            webservice.close()
                }

            Hooks.useEffectDisposable(register,[||])

            if connected.current then str "Connected" else str "Disconnected"
        )