JavaScript coding standards

OOP with JavaScript

Encapsulation

• OOP in JS, Part 1 : Public/Private Variables and Methods

Inheritance

• OOP in JS, Part 2 : Inheritance

Namespaces/packages

Naming convention for packages is lowercase.

Create base class:

var twiki = {}

Create subclass:

twiki.String = {
   // functions here
}

Unit testing

JSUnitContrib

User interface programming

To separate markup and logic and to provide graceful degradation I have been using BehaviourContrib.

For example, if we have a 'normal' link to TWiki Web hometopic: TWiki Web Home, we can use javascript to make it open a popup window. When javascript is not available the link behaviour defaults to opening the page in the current window.

<span class="link%TWIKIWEB%%HOMETOPIC%">[[%TWIKIWEB%.%HOMETOPIC%][TWiki Web Home]]</span>

<script type="text/javascript">
// <![CDATA[
var myrules = {
   '.link%TWIKIWEB%%HOMETOPIC% a' : function(el){
      el.onclick = function() {
         // open in a popup with no other attributes than template 'viewplain'
         launchTheWindow(this.href,null,null,null,"viewplain");
         return false;
      }
   }
};

Behaviour.register(myrules);
// ]]>
</script>

The class name link%TWIKIWEB%%HOMETOPIC% will get expanded to linkTWiki06x01WebHome

See demo page for this code.

Packaging and delivery

JavaScript files can grow large, especially when documentation is added. Of course we wouldn't want to do away with documentation just because of the filesize.

A solution is to compress the files. The tool I've been using is Dojo's ShrinkSafe. The results are quite impressive.

Note that when using Dojo, private members should be placed at the top of the class, followed by priviliged members.

Naming convention is to insert .compressed in the name, for example: twisty.js for the original file and twisty.compressed.js for the compressed file.

Naming conventions

Dojo has a list of Javascript Programming Conventions.

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-- Contributors: ArthurClemens - 29 Oct 2006

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