nojson | Simple Golang library created in order to escape | Reflection library

I am trying to learn WebRTC, I had achieved connecting two RTCPeerConnection in same page and I am now attempting to separate them into two separate pages and connects them. However, after code are written and exchanged offer and answer, I noticed addIceCandidate() on initiator.html will always throw this with null argument

Error at addIceCandidate from queue: TypeError: Failed to execute 'addIceCandidate' on 'RTCPeerConnection': Candidate missing values for both sdpMid and sdpMLineIndex at processCandidateQueue (initiator.html:69)

After some reading, I learnt null is used to indicate ICE Candidate gathering finishes and example here: https://webrtc.github.io/samples/src/content/peerconnection/pc1/ Also executes "addIceCandidate" with argument null when gathering finishes. But I do not understand why I am seeing the error I see at this moment.

What I had tried:

1. I had tried to write a check such that if candidate is null, skip addIceCandidate.
2. Place all connection logic in less buttons to reduce delay between function calls
3. Add adapter-latest.js to each page

Result:

1. Initiator connection state is "fail", receiver connection state is "new". Failed to stream to receiver page.
2. Same error was thrown
3. Error is gone, but connection still fails

initiator.html