socket.js

var socketIO = require('socket.io');
var server = require('http').createServer().listen(7000);
var io = socketIO.listen(server);
console.log((new Date()) + " Server is listening on port 7000");

io.sockets.on('connection', function (client) {
    console.log('New Client Connection: ' + client.id);

    client.on('offer', function (details) {
        client.broadcast.emit('offer', details);
        console.log(`OFFER (${client.id}):`,details.sdp);
        console.log('----------------------------------------------');
    });

    client.on('answer', function (details) {
        client.broadcast.emit('answer', details);
        console.log(`ANSWER (${client.id}):`, details.sdp);
        console.log('----------------------------------------------');
    });
    
    client.on('candidate', function (details) {
        client.broadcast.emit('candidate', details);
        console.log(`CANDIDATE (${client.id}):`);
        console.log(details.sdpMid);
        console.log(details.sdpMLineIndex);
        console.log(details.sdp);
        console.log('----------------------------------------------');
    });

    // Here starts evertyhing!
    // The first connection doesn't send anything (no other clients)
    // Second connection emits the message to start the SDP negotation
    client.broadcast.emit('createoffer', {});
});