var pull = require('pull-stream')
var createEbtStream = require('epidemic-broadcast-trees')
var Obv = require('obv')
//create a datamodel for a reliable chat room.
function createChatModel (id, log) {
//in this example, logs can be a map of arrays,
var logs = {}
if(id) logs[id] = log || []
var onAppend = Obv()
return {
logs: logs,
append: function append (msg) {
(logs[msg.author] = logs[msg.author] || []).push(msg)
onAppend.set(msg)
},
onAppend: onAppend
}
}
function createStream(chat) {
//so the vector clock can be
var vectorClock = {}
for(var k in chat.logs)
vectorClock[k] = chat.logs[k].length
//observables are like an event emitter but with a stored value
//and only one value per instance (instead of potentially many named events)
var stream = createEbtStream(
//pass a get(id, seq, cb)
function (id, seq, cb) {
if(!chat.logs[id] || !chat.logs[id][seq-1])
return cb(new Error('not found'))
cb(null, chat.logs[id][seq-1])
},
//pass append(msg, cb)
function (msg, cb) {
chat.append(msg)
cb()
}
) ({
seqs: vectorClock,
})
chat.onAppend(stream.onAppend)
return stream
}
var alice = createChatModel('alice', [])
var bob = createChatModel('bob')
var as = createStream(alice)
var bs = createStream(bob)
pull(as, bs, as)
//have bob get ready to receive something
bob.onAppend(function (msg) {
console.log('msg at bob:', msg)
})
//have alice send a message to bob
alice.append({author: 'alice', sequence: 1, content: 'hello bob!'})
console.log(0)
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