JSFiddle - React, Tailwind, and code Playground

JavaScript

var pc = new webkitRTCPeerConnection(null, null);
/* global webkitAudioContext */
var wacx = new webkitAudioContext();

function createOffer() {
  var numRequestedAudioTracks = 1;
  while (numRequestedAudioTracks < pc.getLocalStreams().length) {
    pc.removeStream(pc.getLocalStreams()[pc.getLocalStreams().length - 1]);
  }
  pc.createOffer(gotDescription, null, null);
  while (numRequestedAudioTracks > pc.getLocalStreams().length) {
    // Create some dummy audio streams using Web Audio.
    // Note that this fails if you try to do more than one track in Chrome
    // right now.
    var dst = wacx.createMediaStreamDestination();
    pc.addStream(dst.stream);
  }
  //pc.createOffer(gotDescription, null, null);

}

function gotDescription(desc) {
  console.log(desc.sdp);
  if (desc.sdp.indexOf("a=msid:") === -1) {
      alert("pass");
  } else {
      alert("fail");
  }
}

createOffer();