libdatachannel/examples/web/script.js

(function (){
  console.log('Hello');
  const connectButton = document.getElementById('createConnectionBtn');
  connectButton.addEventListener('click', createConnection, false);
})();

function createConnection() {
  const localConnection = new RTCPeerConnection();
  const sendChannel = localConnection.createDataChannel('channel');
  const connectionInfo = {};
  localConnection.onicecandidate = e => {
    if (e.candidate) {
      const candidate = e.candidate.candidate;
      connectionInfo.candidate = candidate;
      const answererUrl = 'http://localhost:8080/answerer.html?connection=' + btoa(JSON.stringify(connectionInfo));
      const createLink = document.createElement('a');
      createLink.setAttribute('href', answererUrl);
      createLink.setAttribute('target', 'new');
      createLink.append('Open me ;)');
      document.body.append(createLink);
      const pollForConnection = setInterval(() => {
        fetch(
          'http://localhost:8000/state/json'
        ).then(response => {
          if (response.status !== 200) {
            throw new Error('bad status ' + response.status);
          }
          return response.json();
        }).then(data => {
          if (data.description) {
            console.log('yes');
            clearInterval(pollForConnection);
            createRemoteConnection(data.description);
          }
          else {
            console.log('no');
          }
        });
      }, 5000);
    }
  };

  localConnection.createOffer().then((desc) => {
    connectionInfo.description = desc.sdp;
    localConnection.setLocalDescription(desc);
  });

  function createRemoteConnection(desc) {
    const remoteDesc = {
      type: 'answer',
      sdp: desc
    };
    localConnection.setRemoteDescription(remoteDesc).then((e) => {
      console.log(e);
    });
  }

  const sendButton = document.getElementById('sendDataBtn');
  sendButton.addEventListener('click', sendMessage, false);
  function sendMessage() {
    const messageText = document.getElementById('sendData').value;
    sendChannel.send(messageText);   
  }
  sendChannel.onmessage = (msg) => {
    document.body.append(msg.data);
  };
}