Using mix

YUI().use('node', function(Y) {
    // This method is in the core of the library, so we don't have to use() any
    // additional modules to access it.  However, this example requires 'node'.

Adding functionality to individual objects

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

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

var Logging = function () {
    var logger = null;
    
    return {
        initLogger : function (logNode) {
            if (!logger) {
                logger = Y.one(logNode);
            }
        },

        log : function (message) {
            if (logger) {
                logger.append('<p>' + message + '</p>');
            }
        }
    }
}();

var PageController = function () {
    var app_const = 12345;

    return {

        getConst : function () { 
            return app_const;
        },

        logConst : function () {
            this.initLogger('#demo_logger');
            this.log('PageController class constant = ' + this.getConst() +
                      ', logged courtesy of object augmentation via Y.mix.');
        }
    };
}();

Y.mix(PageController, Logging);

Y.on('click', PageController.logConst, '#demo_btn', PageController);

Much like augment

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

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