javascript - RTCDataChannel's ReadyState is not 'open'

Question

I'm trying to send text over an RTCPeerConnection with RTCDataChannel using WebRTC's adapter.js, but I'm getting the following error:

Uncaught InvalidStateError:
Failed to execute 'send' on 'RTCDataChannel':
RTCDataChannel.readyState is not 'open'

My code is available via this fiddle and below:

var peerConnection = new RTCPeerConnection(null, {
  optional: [{
    RtpDataChannels: true
  }]
});

peerConnection.ondatachannel = function(event) {
  receiveChannel = event.channel;
  receiveChannel.onmessage = function(event){
    alert(event.data);
  };
};

var dataChannel = peerConnection.createDataChannel("data", {reliable: false});
dataChannel.send("Hello");

Am I doing anything wrong?

Answer 1

I wrote the following code this morning that uses RTCPeerConnection and RTCDataChannel in a single page. The order in which these functions are declared is important.

var localPeerConnection, remotePeerConnection, sendChannel, receiveChannel;

localPeerConnection = new RTCPeerConnection(null, {
  optional: [{
    RtpDataChannels: true
  }]
});

localPeerConnection.onicecandidate = function(event) {
  if (event.candidate) {
    remotePeerConnection.addIceCandidate(event.candidate);
  }
};

sendChannel = localPeerConnection.createDataChannel("CHANNEL_NAME", {
  reliable: false
});

sendChannel.onopen = function(event) {
  var readyState = sendChannel.readyState;
  if (readyState == "open") {
    sendChannel.send("Hello");
  }
};

remotePeerConnection = new RTCPeerConnection(null, {
  optional: [{
    RtpDataChannels: true
  }]
});

remotePeerConnection.onicecandidate = function(event) {
  if (event.candidate) {
    localPeerConnection.addIceCandidate(event.candidate);
  }
};

remotePeerConnection.ondatachannel = function(event) {
  receiveChannel = event.channel;
  receiveChannel.onmessage = function(event) {
    alert(event.data);
  };
};

localPeerConnection.createOffer(function(desc) {
  localPeerConnection.setLocalDescription(desc);
  remotePeerConnection.setRemoteDescription(desc);
  remotePeerConnection.createAnswer(function(desc) {
    remotePeerConnection.setLocalDescription(desc);
    localPeerConnection.setRemoteDescription(desc);
  });
});