Using classical inheritance to contain express controllers and socket events

Coffeescript has +1'ed itself for me lately.  I will tell you why and try to explain.  As far as I know, there is no native support in coffeescript for having a class extend multiple parents classes.  In plain javascript, scope and prototypal inheritance can be confusing, as you'll see later on.

Lets imagine we are taking our express web application and isolating out the app routes and the socket events.  The reason for this is simple:  when a Web class extends the controller and event classes, they can share important pieces of information related to the web server such as a user session or login information.  This will help us later on when implementing socket events for authorized users.

Here is the entire bit of code to get you going.  It is simple, elegant, and for the most part completely readable as long as you have a bit of understanding in regards to the way prototypes in javascript work.

	moduleKeywords = ['included', 'extended']
	class SuperClass
	@include: (obj) ->
	throw('include(obj) requires obj') unless obj
	for key, value of obj.prototype when key not in moduleKeywords
	@::[key] = value
	included = obj.included
	included.apply(this) if included
	@
	class Controller
	constructor: ()->
	@hasController = true
	class Events
	constructor: ()->
	@hasEvents = true
	class Web extends SuperClass
	@include Controller
	@include Events
	constructor: ()->
	Controller.call @
	Events.call @
	module.exports = Web

view raw httpd-container-skel.coffee hosted with ❤ by GitHub

Here is the compiled, fully javascript compliant version.  As you can see, its a bit messy and definitely not as readable as the coffeescript version.

	(function() {
	var Controller, Events, SuperClass, Web, moduleKeywords,
	__indexOf = [].indexOf || function(item) {
	for (var i = 0, l = this.length; i < l; i++) {
	if (i in this && this[i] === item)
	return i;
	}
	return -1;
	},
	__hasProp = {}.hasOwnProperty,
	__extends = function(child, parent) {
	for (var key in parent) {
	if (__hasProp.call(parent, key))
	child[key] = parent[key];
	}
	function ctor() {
	this.constructor = child;
	}
	ctor.prototype = parent.prototype;
	child.prototype = new ctor();
	child.__super__ = parent.prototype;
	return child;
	};
	moduleKeywords = ['included', 'extended'];
	SuperClass = (function() {
	function SuperClass() {}
	SuperClass.include = function(obj) {
	var included, key, value, _ref;
	if (!obj) {
	throw 'include(obj) requires obj';
	}
	_ref = obj.prototype;
	for (key in _ref) {
	value = _ref[key];
	if (__indexOf.call(moduleKeywords, key) < 0) {
	this.prototype[key] = value;
	}
	}
	included = obj.included;
	if (included) {
	included.apply(this);
	}
	return this;
	};
	return SuperClass;
	})();
	Controller = (function() {
	function Controller() {
	this.hasController = true;
	}
	return Controller;
	})();
	Events = (function() {
	function Events() {
	this.hasEvents = true;
	}
	Events.prototype.getEvents = function() {
	return [];
	};
	return Events;
	})();
	Web = (function(_super) {
	__extends(Web, _super);
	Web.include(Controller);
	Web.include(Events);
	function Web() {
	Controller.call(this);
	Events.call(this);
	}
	return Web;
	})(SuperClass);
	module.exports = Web;
	}).call(this);

view raw httpd-container-skel.js hosted with ❤ by GitHub

Happy coding.