simplexPeer.js

var simplexPeer = new function() {

    // const
    this.ICE_SERVERS = [{
        urls: "stun:stun.l.google.com:19302",
      }
    ]

    this.CHANNEL_KEY  = 'webrtc/channel';
    this.SENDER_KEY   = 'webrtc/sender-description';
    this.RECEIVER_KEY = 'webrtc/receiver-description';

    // memebers
    this.peer_id = null;
    this.socket  = null;
    this.peer    = null;
    this.channel = null;
    this.session = null;
    this.type    = null;

    // utils
    this.trace = function(msg) {
      var now = (window.performance.now() / 1000).toFixed(3);
      console.log(now + ': ', msg);
    }

    this.recordKey = function() {
      return "webrtc/" + this.peer_id + "-" + this.type;
    }

    this.socketConnect = function(wssUrl) {
      
      var _this = this;
      this.socket = deepstream( wssUrl );
      this.socket.login();

      // remote description callback
      var remoteDesc = this.socket.record.getRecord( this.peer_id + "-" + this.RECEIVER_KEY );
      
      remoteDesc.subscribe( function() {

        // if we are the sender...
        if (_this.type === "sender") {
          console.log("sender: setting remote");
          _this.peer.setRemoteDescription(remoteDesc.get());
        }

        // if we are the receiver
        if (_this.type === "receiver") {
          console.log("receiver: setting local");
          _this.peer.setLocalDescription(remoteDesc.get());
        }
      });

      // local description callback
      var localDesc = this.socket.record.getRecord( this.peer_id + "-" + this.SENDER_KEY );
      localDesc.subscribe( function() {

        // if we are the sender...
        if (_this.type === "sender") {
          console.log("sender: setting local");
          _this.peer.setLocalDescription(localDesc.get());
        }

        // if we are the receiver
        if (_this.type === "receiver") {
          console.log("receiver: setting remote");
          _this.peer.setRemoteDescription(localDesc.get());
        }
      });
    }

    this.peerConnect = function(name) {
      var _this = this;
      var pcConstraint = null;

      _this.peer = new RTCPeerConnection( { iceServers: _this.ICE_SERVERS }, pcConstraint);
      _this.trace('new peerConnection.');

      // ICE Candidate callbacks
      var candidateSuccessful = function() {
        _this.trace("ICE added successfully")
      };

      var candidateError = function(err) {
        // _this.trace("failed to add ICE candidate: ");
        // _this.trace(err);
      };

      _this.peer.onicecandidate = function(event) {        
        _this.peer.addIceCandidate(event.candidate)
        .then( 
          function() {
            candidateSuccessful();
          },
          function(err) {
            candidateError(err);
          }
        );
  
        // trace('ICE candidate: \n' + (event.candidate ? event.candidate.candidate : '(null)'));
      }

      // webrtc data channel
      var channelConstraint = null;
      _this.channel = _this.peer.createDataChannel(name, channelConstraint);

      var channelStateChange = function(arg1) {
        _this.trace("on channelStateChange: ");
        _this.trace("got: ", arg1);
      }

      _this.channel.onopen = channelStateChange;
      _this.channel.onclose = channelStateChange;
    }

    this.createOfferCallback = function(_this, desc) {
      var record = _this.socket.record.getRecord( this.peer_id + "-" + this.SENDER_KEY );

      record.set({
        id: _this.peer_id,
        type: desc.type,
        sdp: desc.sdp,
      });
    }

    this.createOfferError = function(err) {
      this.trace("createOfferError");
      this.trace(err);
    }

    this.createAnswerCallback = function(_this, desc) {
      var record = _this.socket.record.getRecord( this.peer_id + "-" + this.RECEIVER_KEY );

      record.set({
        id: _this.peer_id,
        type: desc.type,
        sdp: desc.sdp,
      });
    }

    this.createAnswerError = function(_this, err) {
      _this.trace("createAnswerError");
    }
    
    this.connect = function(name, wss, type, callback) {
      var _this = this;

      this.peer_id = Math.random().toString(36).substring(7);
      this.type = type;

      this.peerConnect(name);
      this.socketConnect(wss);

      if (type === "sender") {
        this.peer.createOffer().then(
          function(desc) {
            _this.createOfferCallback(_this, desc);
          },
          function(err) {
            _this.createOfferError(_this, err);
          }
        );
      }

      if (type === "receiver") {
        var offerDesc = this.socket.record.getRecord( this.peer_id + "-" + this.SENDER_KEY ).get();

        if (offerDesc.type === 'offer') {
          this.peer.createAnswer().then(
            function(desc) {
              _this.createAnswerCallback(_this, desc);
            },
            function(err) {
              _this.createAnswerError(_this, err);
            }
          );
        }
      }
    };

    // ===========================================
    // == Public API
    // ===========================================
    this.connectSender = function(name, wss, callback) {
      this.connect(name, wss, "sender", callback);
    }

    this.connectReceiver = function(name, wss, callback) {
      this.connect(name, wss, "receiver", callback);
    }
}

export default simplexPeer;