YUI Howto: Use make internal functions available out of a modules scope.

yui-namespaces.js

YUI.add('module-name', function (Y) {
  'use strict';
  
  var init = function(){
    // Do Something...
  };
  
  Y.ModuleName = {
    init: init
  };
}, '0.1', {requires: ['node', 'event']});