Promise future and past

Future Promise

var foo = function(a){
     var promise = new Promise();
     asyncAjaxFunction(a).done(function(){
      promise.resolve();
    }).fail(function(){
       promise.reject();
    })
};

foo.then(function(){
 // all ok - resolve
}, function(){
 // wrong - reject
});

Nested Promises

// using the code of above

Promise.when(foo(1), foo(2), foo(3)).then(function(){
 // all ok - resolve
}, function(){
 // wrong - reject
});

Past nested callback

var foo = function(callback){
     asyncAjaxFunction().done(function(){
      callback(true);
    }).fail(function(){
      callback(false);
    })
};