JavaScript development – libraries and OOP coding conventions

As I wrote earlier I’m currently porting our ActionScript framework to JavaScript, which basically means I’m diving into JavaScript from and ActionScript developers perspective. Of course I’m still at the beginning of becoming a good JavaScript developer, but I made some progress I’d like to share.

I’ll start right away recommending some core libraries:

  • Objs – Namespaces and class inheritance
  • PureMVC Objs – MVC framework (Objs port)
  • JS-Signals – Event / Messaging system
  • jQuery – Helps with core functionalities and cross browser issues

The existing ActionScript project is based on PureMVC so it was obvious to settle on the same horse, but it wasn’t easy to decide which PureMVC port! This is a fundamental decision because it also defines how to write OOP JavaScript.

Objs has a clean syntax (and documentation) and after developer M. Saunier Frédéric was kind enough to resolve my license problem I used his lightweight version with one little customization: I changed the constructor function name from initialize() to __construct() as it looks more appropriate to me and I already used some initialize() functions for different tasks.
Changed versions: customized puremvc-objs-2.0.js and customized objs-2.0.js.

ActionScript developers probably know Robert Penners AS-Signals but I never implemented it in one of my projects so now I use the concept with JS-Signals.

And of course I also use jQuery with it’s great developer community.

So this is how a “class” with applied coding conventions would look like:

/**
 * Created by derRaab(); - http://blog.derRaab.com
 */
( function () {
 
	/**
	 * Namespace vars for minification (only necessary if used multiple times, but you get the idea how to save strings)
	 */
	var nsCom = "com.",
		nsComDerraab = nsCom+ "derraab.",
		nsComDerraabExamples = nsComDerraab+ "examples.",
 
	/**
	 * Final class
	 */
	ExampleClass,
 
	/**
	 * Temporary class prototype (separated because that helps with IDE code completion)
	 */
	ExampleClassPrototype =
	{
		/**
		 * Without leading underscore part of public API.
		 *
		 * @type {Boolean}
		 * @private
		 */
		publicVar : false,
 
		/**
		 * With one leading underscore part of protected API,
		 * Use it only in this and it's subclasses.
		 *
		 * @type {String}
		 * @private
		 */
		_protectedVar : "",
 
		/**
		 * With two leading underscores use it only in this class!
		 * @type {Number}
		 * @private
		 */
		__privateVar : 0,
 
		/**
		 * <code>ExampleClass</code> constructor (called on instance creation!)
		 *
		 * @param {Number}	privateValue
		 * @param {String}	protectedValue
		 * @param {Boolean}	publicValue
		 */
		__construct: function( privateValue, protectedValue, publicValue )
		{
			// Call to superclass constructor (See Objs documentation)
			// ExampleClass.$super.__construct.apply( this, arguments );
 
			this.__privateVar	= privateValue;
			this._protectedVar	= protectedValue;
			this.publicVar		= publicValue;
 
			// Use static values
			this.__privateVar = ExampleClass.DEFAULT_NUMBER;
		},
 
		/**
		 * Without leading underscore part of public API.
		 */
		publicMethod: function()
		{
		},
 
		/**
		 * With one leading underscore part of protected API,
		 * Use it only in this and it's subclasses.
		 */
		_protectedMethod: function()
		{
		},
 
		/**
		 * With two leading underscores use it only in this class!
		 */
		__privateMethod: function()
		{
		}
	};
 
	/**
	 * Let Objs create our "real" class (see Objs documentation for more details
	 */
	ExampleClass = Objs( nsComDerraabExamples + "ExampleClass", ExampleClassPrototype );
 
	/**
	 * Now add some "static" values
	 */
	ExampleClass.DEFAULT_BOOLEAN = true;
	ExampleClass.DEFAULT_STRING = "georgeous";
	ExampleClass.DEFAULT_NUMBER = 1;
 
}());

This style is still evolving but I think this is kind of how I like to work.

I suggest you read my last post regarding JavaScript library development using ANT and YUICompressor which might help you with project setup and code compression.

And a word to JavaScript IDEs:

I bought WebStorm but it doesn’t integrate ANT. Luckily I earned a IntelliJ IDEA license earlier this year but I’m not absolutely happy with it. It uses a lot of system resources, needs to set up an Java project and so on. Any hints?

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