gistfile1.js

BaseView = Y.Base.create('baseview', Y.View,[],{
  //
  // my awesome BaseView statics and methods
  //
},{
 ATTRS:{
   //
   // my awesome BaseView ATTRS
   //
 }
});



// OPTION 1 -  extend the already extended BaseView
ViewA = Y.Base.create('viewA', BaseView,[],{
  //
  // awesome ViewA statics/methods that replaces some BaseView stuff and adds new stuff
  //
},{
 ATTRS:{
   //
   // awesome ViewA ATTRS that replaces some BaseView stuff and adds new stuff
   //
 }
}); 


// OPTION 2 - extend View and include BaseView as extension
ViewA = Y.Base.create('viewA', Y.View, [BaseView], {
  //
  // awesome ViewA statics/methods that replaces some BaseView stuff and adds new stuff
  //
},{
 ATTRS:{
   //
   // awesome ViewA ATTRS that replaces some BaseView stuff and adds new stuff
   //
 }
});