// prepare
var adef=Promise.defer();
var bdef=Promise.defer();
var a=adef.promise;
var b=bdef.promise;
a.then(function(){console.log("A");});
b.then(function(){console.log("B");});
var ab=Promise.all([a, b]);
ab.then(function(){console.log("AB");});
// stop here
adef.resolve();
bdef.resolve();