My naive attempt at multiplexing/demultiplexing Scuttlebutt Model streams.

scuttlebutt_muxdemux_test.js

var MuxDemux = require('mux-demux');
var net = require('net');
var Model = require('scuttlebutt/model');

var aModel = new Model
var aModelStream = aModel.createStream()

var bModel = new Model
var bModelStream = bModel.createStream()
// Server

var server = new net.createServer(function (stream) {
    var mx = new MuxDemux
    mx.pipe(stream).pipe(mx)

    var channel1 = mx.createStream('channel1')
    var channel2 = mx.createStream('channel2')

    aModelStream.pipe(channel1)
    bModelStream.pipe(channel2)

    mx.on('connection', function(stream) {
        if (stream.meta === 'channel1') {
            stream.pipe(aModelStream)
        }
        else if (stream.meta === 'channel2') {
            stream.pipe(bModelStream)
        }
    })

}).listen(8000)

aModel.on('update', function(data) {
    console.log('A updated with: ' + JSON.stringify(data))
})

bModel.on('update', function(data) {
    console.log('B updated with: ' + JSON.stringify(data))
})

// Client

var cModel = new Model
var cModelStream = cModel.createStream()

var dModel = new Model
var dModelStream = dModel.createStream()

server.on('listening', function() {

    var stream = net.connect(8000, function() {
        var mx = new MuxDemux
        mx.pipe(stream).pipe(mx)

        var channel1 = mx.createWriteStream('channel1')
        var channel2 = mx.createWriteStream('channel2')

        cModelStream.pipe(channel1)
        dModelStream.pipe(channel2)

        mx.on('connection', function(stream) {
            if (stream.meta === 'channel1') {
                stream.pipe(cModelStream)
            }
            else if (stream.meta === 'channel2') {
                stream.pipe(dModelStream)
            }
        })
    })
})

cModel.on('update', function(data) {
    console.log('C updated with: ' + JSON.stringify(data))
})

dModel.on('update', function(data) {
    console.log('D updated with: ' + JSON.stringify(data))
})

setTimeout(function() {
    aModel.set('bob', {a: 'valuea'})
}, 1000)

setTimeout(function() {
    bModel.set('bob', {b: 'valueb'})
}, 2000)

setTimeout(function() {
    cModel.set('bob', {c: 'valuec'})
}, 3000)

setTimeout(function() {
    dModel.set('bob', {d: 'valued'})
}, 4000)

there are a few small mistakes here, I've fixed them in my fork.
https://gist.github.com/dominictarr/5111698

basically,

• create the scuttlebutt streams inside the server handler
• scuttlebutt is used duplex style pipe: a.pipe(b).pipe(a)
• use mx.on('connection',...) on one side, and mx.createStream(...) on the other
• always use mx.createStream() for duplex, not mx.createWriteStream()