meteor-ddp-pseudo.js

// DDP Server
// Use an implementation of WebSocket Server such as SockJS
ddpServer.socket = WebSocketServer
ddpServer.socket.onData = (msg) => {
  switch(msg):
   case 'connect':
     check whether WebSocket connection
     socket.send({msg: 'connected', ...})
   case 'method':
     result = methodsMap.get(msg.methodID).invoke()
     socket.send({'result': ...})
   case 'sub':
     publicationsMap.get(msg.subId).push(new Subscription)
     socket.send({msg: 'ready', ...})
   
   case ...
}

ddpServer.publish = (name) => {
  publicationsMap.push(name)
}

dppServer.methods = (names) => {
  methodsMap.push(names)
}


// DDP Client
// Simply use a WebSocket client to open connection 
// and send messages to the WebSocket Server
ddpClient.ws = WebSocket
ddpClient.connect = () => {
  ws.on('open', () => ws.send(EJSON({msg: 'connect', ...})))
}

ddpClient.call = () => {
  ws.send(EJSON({msg: 'method', ...}))
}

ddpClient.subscribe = () => {
  ws.send(EJSON({msg: 'sub', ...}))
}