Lazy Views pattern

gistfile1.js

YUI().use('app', function (Y) {
  
  var MyApp = Y.Base.create('myApp', Y.App, [], {
    
    views: {
      person: {
        type: 'PersonView'
      }
    },
    
    showPerson: function () {
      var self = this.set('loading', true);
      
      // ask for the module containing the view
      Y.use('person-view', function () {
        // the view is now available, so just create it
        self.showView('person', {
          model: self.get('model')
        });
      });
    }
    
  }, {
    ATTRS: {
      loading: {
        value: false
      }
    }
  });
  
});