fix(ws_js): use close codes browsers accept

WebSocket.close throws for any code other than 1000 and 3000-4999, so
closing with the codes this package uses itself (1001 from CloseNow, 1008,
1009, 1011) failed and left the socket open, and under TinyGo the throw is
a fatal panic. Send 1000 for those codes while keeping the requested code
in the local close error, and stop the error handler from closing, since a
close event always follows and waiting for it inside the callback deadlocks.

Author: 0pcom

ws_js.go

@@ -101,8 +101,9 @@ func (c *Conn) init() {
 	})
 
 	c.releaseOnError = c.ws.OnError(func(v js.Value) {
+		// A close event always follows. Closing here would wait for it
+		// inside this callback and deadlock.
 		c.setCloseErr(errors.New(v.Get("message").String()))
-		c.closeWithInternal()
 	})
 
 	c.releaseOnMessage = c.ws.OnMessage(func(e wsjs.MessageEvent) {
@@ -259,6 +260,9 @@ func (c *Conn) exportedClose(code StatusCode, reason string) error {
 	})
 
 	c.setCloseErr(ce)
+	if code != StatusNormalClosure && (code < 3000 || code > 4999) {
+		code = StatusNormalClosure // Browsers throw on any other code.
+	}
 	err := c.ws.Close(int(code), reason)
 	if err != nil {
 		return err

ws_js_test.go

@@ -52,3 +52,31 @@ func TestWasmDialTimeout(t *testing.T) {
 		t.Fatal("wasm context dial timeout is not working", time.Since(beforeDial))
 	}
 }
+
+func TestWasmCloseStatus(t *testing.T) {
+	t.Parallel()
+
+	// The library closes with these itself, but browsers only accept
+	// 1000 and 3000-4999.
+	for _, code := range []websocket.StatusCode{
+		websocket.StatusGoingAway,
+		websocket.StatusPolicyViolation,
+		websocket.StatusMessageTooBig,
+		websocket.StatusInternalError,
+	} {
+		t.Run(code.String(), func(t *testing.T) {
+			t.Parallel()
+
+			ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
+			defer cancel()
+
+			c, _, err := websocket.Dial(ctx, os.Getenv("WS_ECHO_SERVER_URL"), &websocket.DialOptions{
+				Subprotocols: []string{"echo"},
+			})
+			assert.Success(t, err)
+
+			err = c.Close(code, "")
+			assert.Success(t, err)
+		})
+	}
+}