A minimal WebRTC DataChannel example

webrtc_example.js

/**
 * A minimal example of a WebRTC data channel on a single host.
 * After running, use dcRemote.send('message') or dcLocal.send('message') to send messages between local and remote peers
**/

let peerLocal = new RTCPeerConnection();
let peerRemote = new RTCPeerConnection();

peerLocal.onconnectionstatechange = function(e) {
	console.log('peerLocal', 'onconnectionstatechange', e);
};
peerLocal.ondatachannel = function(e) {
	console.log('peerLocal', 'ondatachannel', e);
};
peerLocal.onsignalingstatechange = function(e) {
	console.log('peerLocal', 'onsignalingstatechange', peerLocal.signalingState);
};
peerLocal.onicegatheringstatechange = function(e) {
	console.log('peerLocal', 'onicegatheringstatechange', peerLocal.iceGatheringState);
};
peerLocal.onicecandidate = function(e){
	console.log('peerLocal', 'onicecandidate', e.candidate);
	//Share ICE candidates with peerRemote
	if(e.candidate!=null)
			peerRemote.addIceCandidate(e.candidate);
};
peerLocal.onnegotiationneeded = function(e) {
	console.log('peerLocal', 'onnegotiationneeded', e);

};
let dcLocal = peerLocal.createDataChannel('rtcdc');
dcLocal.onopen = function(e) {
	console.log('dcLocal', 'onopen', e);
	console.log('dcLocal.send("message") to send from server');
};
dcLocal.onmessage = function(e) {
	console.log('dcLocal', 'onmessage', e.data);
};
dcLocal.onerror = function(e) {
	console.error('dcLocal', 'onerror', e);
};
dcLocal.onclose = function(e) {
	console.log('dcLocal', 'onclose', e);
};
let dcRemote = null;

peerRemote.onconnectionstatechange = function(e) {
	console.log('peerRemote', 'onconnectionstatechange', e);
};
peerRemote.ondatachannel = function(e) {
	// peerLocal started a data channel, so connect to it here
	console.log('peerRemote', 'ondatachannel', e);
	dcRemote  = e.channel;
	dcRemote.onopen = function(e) {
		console.log('dcRemote', 'onopen', e);
		console.log('dcRemote.send("message") to send from remote');

	};
	dcRemote.onmessage = function(e) {
		console.log('dcRemote', 'onmessage', e.data);
	};
	dcRemote.onerror = function(e) {
		console.error('dcRemote', 'onerror', e);
	};
	dcRemote.onclose = function(e) {
		console.log('dcRemote', 'onclose', e);
	};

};
peerRemote.onsignalingstatechange = function(e) {
	console.log('peerRemote', 'onsignalingstatechange', peerRemote.signalingState);
};
peerRemote.onicegatheringstatechange = function(e) {
	console.log('peerRemote', 'onicegatheringstatechange', peerRemote.iceGatheringState);
};
peerRemote.onicecandidate = function(e){
	//Share ICE candidates with peerLocal
	console.log('peerRemote', 'onicecandidate', e);
	if(e.candidate!=null)
			peerLocal.addIceCandidate(e.candidate);
};
peerRemote.onnegotiationneeded = function(e) {
	console.log('peerRemote', 'onnegotiationneeded', e);

};
var options =null;// { offerToReceiveVideo: true, offerToReceiveAudio: true };


console.log('peerLocal', 'createOffer');
let peerLocalOffer = await peerLocal.createOffer(options);

console.log('peerLocal', 'setLocalDescription', peerLocalOffer);
await peerLocal.setLocalDescription(peerLocalOffer);

console.log('peerRemote', 'setRemoteDescription', peerLocalOffer);
await peerRemote.setRemoteDescription(peerLocalOffer);

console.log('peerRemote', 'setRemoteDescription');
let peerRemoteAnswer = await peerRemote.createAnswer();

console.log('peerRemote', 'setLocalDescription', peerRemoteAnswer);
await peerRemote.setLocalDescription(peerRemoteAnswer);


console.log('peerLocal', 'setRemoteDescription', peerRemoteAnswer);
await peerLocal.setRemoteDescription(peerRemoteAnswer);