q promise example

q_promise.js

function addAsync(data) { 
   var d = Q.defer(); 
   setTimeout(function() {  
      console.log('data in ' + data); 
      if (data === 2) { 
         d.reject("rejected!"); 
      } else {
         d.resolve(data + 1);
      } 
    },
    1000); 
   return d.promise; 
}
var start_with = 1;
Q.fcall(
    addAsync(start_with)
   .then(addAsync)
   .then(addAsync)
   .then(
      function(result) { console.log("result " + result) },
      function(err) { console.log("error " + err) }
    )
    
);

console.log('done');