promises.js

//assuming angulars $http

function fetchQuestions(url){
  return $http.get(url)
    .then(response => response.data)
    .then(extractObject('answer', receiveAnswers))
    .then(receiveQuestions);
}

function extractObject(key, fc){
  return function(items){
    fn(items.filter(item => !!item[key]).map(item => item[key]));
    return items;
  }
}

function receiveAnswers(answers){
  // store answers
}

function receiveQuestions(questions){
  // store questions
}