YUI example

gistfile1.js

    YUI().use(
        "console",
        "ep-ui-builder",
        function (Y) {
            Y.on(
                "domready",
                function () {
                    Y.log("index - building UI");
                    try {
                        Y.EP.UI.Build ();
                    }
                    catch (ex) {
                        Y.log("index - in UI build catch");

                        Y.one("#ui-loading").remove();
                        Y.one("body").setContent("Failed to build UI: " + ex);
                        throw(ex);

                        return;
                    }

                    // hide our loading screen
                    Y.log("index - hiding loading message");
                    Y.on(
                        'contentready',
                        function () {
                            Y.log("index - contentready");
                            Y.one("#ui-loading").remove();
                        },
                        '#ep-ui-window'
                    );
                }
            );
        }
    );

YUI.add(
    "ep-ui-builder",
    function (Y) {
        var Clazz = Y.Base.create (
            "ep_ui_builder",
            Y.Base,
            [], 
            {       
                _left:  null,
                _right: null,
                        
                initializer: function (config) {
                    Y.log(Clazz.NAME + "::initializer");

                    this._right  = new Y.EP.UI.Right (
                        {
                            render: true
                        }
                    );                      
                    this._left  = new Y.EP.UI.Left (
                        {
                            render: true
                        }
                    );
                },      
                    
                destructor: function () {
                    Y.log(Clazz.NAME + "::destructor");
                    
                    this._left.destroy();
                    this._left  = null;
                    this._right.destroy();
                    this._right  = null;
            },          
            {               
                ATTRS: {}   
            }           
        );              
                    
        //      
        // set up a function to build a singleton to wrap access to the UI builder
        // by creating an instance if one doesn't already exist, otherwise returns
        // the existing one the build method should then only ever be called once
        //
        var instance = null;
        Y.namespace("EP.UI").Build = function (config) {
            if (! instance) {
                instance = new Clazz (config);
            }
            return instance;
        };  
    },      
    "@VERSION@",
    {   
        requires: [
            "base-build"
            ,"ep-ui-left"
            ,"ep-ui-right"
        ]           
    }                   
);