JQuery.Deferred is the most important client-side tool you have (eng.wealthfront.com)

I really like the fact that jQuery's AJAX methods were converted to support this.

yes jQuery.Deferred is a very elegant solution to nested callbacks et all.... I have got it at the heart of the Single Page Application Architecture I am building currently.

e.g. stionaJS.DAL.authenticate(creds) .pipe(listDomains) .done(withMultiUserDomain) .done(withSingleUserDomain) .fail(failedAuthentication);