Websockets over WebAssembly generated by golang?

Question

Is it possible to write a Websocket client in wasm over go? I have tried using gorilla/websocket, but no success:

func main() {
    ws := func(this js.Value, inputs []js.Value) interface{} {
        go func() {
            wsDial, r, err := websocket.DefaultDialer.Dial("ws://localhost:3000/ws", nil)
            fmt.Println(wsDial, r, err)
        }()
        return nil
    }

    js.Global().Set("ws", js.FuncOf(ws))

    select {}
}

I get the following error when calling ws():

dial tcp: Protocol not available

Answer 1

I have solved it by retrieving the WebSocket object from the global JavaScript object, which in my case is window because I am running this in a browser. I have used only the "syscall/js" library. It looks like this:

ws := js.Global().Get("WebSocket").New("ws://localhost:8080/ws")

ws.Call("addEventListener", "open", js.FuncOf(func(this js.Value, args []js.Value) interface{} {
    fmt.Println("open")

    ws.Call("send", js.TypedArrayOf([]byte{123}))
    return nil
}))

Answer 2

Have a look at the gopherJS websocket library. This one was created to run in the browser (originally js).

I recently saw a youtube video with it being in use in WASM but I couldn't find it any more.