promiseChain.js

/*
* ajaxGET
* -- Custom wrapper around the Jquery GET method
* -- when the request is complete, it returns the response using
*   the 'finish' callback
*/
var ajaxGET = function(url, finish){
    $.get(url).done(function(data){
        finish(data);
    });
}

/*
* Main - start here
*/
$(document).ready(function(){

    //1 - get google
    var first = function(){
        return new Promise(function(resolve){
            ajaxGET("http://google.com",function(googData){
                console.log("---> got first");
                //do something with googData
                resolve();
            });
        });
    }
  
  
    //2 - get apple
    var second = function(){
        return new Promise(function(resolve){
            ajaxGET("http://apple.com",function(appleData){
                console.log("---> got second");
                //do something with appleData
                resolve();
            });
        });
    }
    
    //3 - get amazon
    var third = function(){
        return new Promise(function(resolve){
            ajaxGET("http://amazon.com",function(amData){
                console.log("---> got third");
                //do something with amData
                resolve();
            });
        });
    }
    
    //Start sequential GET using chained promises
  
    first().then(second).then(third);
});