Move to Subscription model

server/eventStreamSource.js

@@ -1,9 +1,41 @@
 import { EventEmitter } from 'events';
+import { nanoid } from 'nanoid';
 
 const Stream = new EventEmitter;
 
+// After Stream starts, send initStream event
+Stream.on('open', ()=>{
+	Stream.emit('sendUpdate', 'initStream', { time: new Date });
+});
+
+// Create array of stream subscribers
+const subscribers = [];
+
+// Listener functions
+const subscribe = function(res){
+	const id = nanoid();
+	subscribers.push({ id, 'stream': res });
+
+	res.write(`event: subscribe\ndata: { id: ${id} }\n\n`);
+	return id;
+};
+
+const unsubscribe = function(id){
+	subscribers = subscribers.filter((sub)=>{ return sub.id != id; });
+};
+
+// Create global sendUpdate listener
+Stream.on('sendUpdate', (event, data)=>{
+	console.log('Event:', event, '\nData:', data);
+	subscribers.forEach((sub, idx)=>{
+		sub?.stream?.write(`event: ${event}\ndata: ${JSON.stringify(data)}\n\n`);
+	});
+});
+
 export default {
 	emit : function(event) {return Stream.emit(event, ...([...arguments].slice(1)));},    // Arguments doesn't work for arrow functions
 	on   : (event, listener)=>{return Stream.on(event, listener);},
-	off  : (event, listener)=>{return Stream.off(event, listener);}
+	off  : (event, listener)=>{return Stream.off(event, listener);},
+	subscribe,
+	unsubscribe
 };