currying

index.js

var o = '{ "user": "tu vieja", "posts": [ { "title": "title 1", "contents": "..." }, { "title": "title 2", "contents": "..." } ] }';

var fetchShit = function() {
  var def = $.Deferred();

  setTimeout(function() {
    def.resolve(o);
  }, 2000);
  
  return def.promise();
};

fetchShit()
  .then(JSON.parse)
  .then(function(data){ return data.posts })
  .then(function(posts){
      return posts.map(function(post){ return post.title })
  })