then.js

p.then($A.getCallback(function(response) {
  //do something
  console.log('success response ' + response);
  return 'success';
}).then(function(message){
  if(message == 'success'){
    // do something
    console.log('message: ' + message);
  }
}).catch(function(error){
  //do something
  console.log('error:' , error);
})