My understanding (partially aided by this post: <a href="http://www.sitepen.com/blog/2010/05/03/robust-promises-with-dojo-deferred-1-5/" target="_blank">http://www.sitepen.com/blog/2010/05/03/robust-promises-with-dojo-deferred-1-5/</a> ) is that Dojo provides both twisted-style &quot;addCallback&quot; and CommonJS-style &quot;then&quot; methods.