YAHOO.lang is packaged with the YAHOO Global Object

YAHOO.lang comes bundled with the YAHOO Global Object.

<script type="text/javascript" src="http://yui.yahooapis.com/2.5.1/build/yahoo/yahoo-min.js"></script>

If you are using any other YUI component on your page, you should already have YAHOO.lang available.

Adding functionality to individual objects

Static classes, such as YAHOO.util.Dom, are implemented as object literals with keys corresponding to public class methods. As such, static classes aren't candidates for instantiation or prototype extention. To add functionality to static classes, you need to work with the class's object literal.

In this example, augmentObject is used to add a set of behaviors to a static class.

We'll create a namespace YAHOO.example.addons to hold common packages of static methods and members. In this namespace, we'll create a set of logging functions.

YAHOO.namespace('example.addons'); YAHOO.example.addons.Logging = function () { var logger = null; // public methods return { initLogger : function (logNode) { if (!logger) { logger = YAHOO.util.Dom.get(logNode); } }, log : function (message) { if (logger) { logger.innerHTML += '<p>' + message + '</p>'; } } } }(); // Execute the function, returning the object literal

Now a targeted class that would benefit from these methods can add them using augmentObject while keeping its source focused and unique.

// Static class with greater purpose YAHOO.example.PageController = function () { var app_const = 12345; // Public API return { getConst : function () { return app_const }, logConst : function () { this.initLogger('demo_logger'); this.log('PageController class constant = ' + this.getConst() + '. Logged courtesy of augmentation'); } }; }(); // Augment PageController with the Logging methods YAHOO.lang.augmentObject( YAHOO.example.PageController, YAHOO.example.addons.Logging); YAHOO.util.Event.on('demo_btn','click', YAHOO.example.PageController.logConst, YAHOO.example.PageController, true);

Much like YAHOO.lang.augmentProto

augmentObject works in similar fashion to augmentProto. In fact, augmentProto uses augmentObject under the hood. However, rather than adding functionality to class definitions (i.e. function prototypes), augmentObject can work with any object, including object literals and class instances.

See augmentProto and extend for other techniques to help manage your code structure.