wasm-client: close client conn in a goroutine

Close the client connection in a goroutine. This fixes a bug that was
introduced with the upgrade to grpc v0.18.1. The caused the websocket
to freeze during closure when the client disconnected, and therefore
the entire wasm-client would freeze.
When closing the connection in a goroutine, the websocket is closed
correctly.

Author: ViktorT-11

cmd/wasm-client/main.go

@@ -290,10 +290,14 @@ func (w *wasmClient) IsConnected(_ js.Value, _ []js.Value) interface{} {
 
 func (w *wasmClient) Disconnect(_ js.Value, _ []js.Value) interface{} {
 	if w.lndConn != nil {
-		if err := w.lndConn.Close(); err != nil {
-			log.Errorf("Error closing RPC connection: %v", err)
-		}
-		w.lndConn = nil
+		// We launch the closure of the connection in a goroutine to avoid
+		// that the JS websocket freezes and blocks while closing.
+		go func() {
+			if err := w.lndConn.Close(); err != nil {
+				log.Errorf("Error closing RPC connection: %v", err)
+			}
+			w.lndConn = nil
+		}()
 	}
 
 	return nil