https://npmjs.org/package/webrtc.io-client says:
Usage
rtc.createStream({"video": true, "audio":true}, function(stream){ // get local stream for manipulation } rtc.connect('ws://yourserveraddress:8001', optionalRoom); //
then a bunch of callbacks are available
You can set the STUN server by calling rtc.SERVER = "STUN stun.l.google.com:19302" and set your server. The default STUN server used by the library is one from google.
Can I use the same STUN server for my commercial app too?