pub-sub pattern implemented with Harmony Proxies.

harmony-pubsub.js

//const Proxy = require('harmony-proxy');

function Publisher() {
	this.subscribers = [];
	var self = this;
	this.public = new Proxy({}, {
		get: function (target, name) {
			return target[name];
		},
		set: function (target, name, value) {
			target[name] = value;
			self.publish(target);
		}
	});
}
	Publisher.prototype.subscribe = function (subscriber) {
		this.subscribers.push(subscriber);
	}
	
	Publisher.prototype.publish = function (change) {
		this.subscribers.forEach(function (subscriber) {
			subscriber.notify(change);
		});
	}
	
function Subscriber(publisher) {
	console.assert(publisher instanceof Publisher, "Subscribers can only be subscribed to a Publisher");
	this.listeners = [];
	publisher.subscribe(this);
}
	Subscriber.prototype.notify = function (change) {
		this.listeners.forEach(function (listener) {
			listener.call(this, change);
		}, this);
	}
	
	Subscriber.prototype.notified = function (listener) {
		this.listeners.push(listener);
	}
	
	

const moon = new Publisher;
const tide = new Subscriber(moon);
tide.notified(function (moon) {
	console.log(moon.type);
});

moon.public.type = 'full';