type fixes and some bugfixes

lib/Transport.js

@@ -561,8 +561,10 @@ class Transport extends Emitter
 		if ("relay"===candidate.getType())
 		{
 			//Get relay ip and port
-			ip   = candidate.getRelAddr();
-			port = candidate.getRelPort();
+			const [relIp, relPort] = [candidate.getRelAddr(), candidate.getRelPort()];
+			if (!relIp || !relPort)
+				throw new Error("relay candidate is lacking relay IP or port");
+			[ip, port] = [relIp, relPort];
 		} else {
 			//Get ip and port
 			ip   = candidate.getAddress();