Getting asynchronous POST to the top level Return (jQuery contextMenu Asynchronous)

test.js

  $('#vocab').contextMenu({
    selector: ".entry",
    build: function($trigger, e) {
      e.preventDefault();

      function buildMenu(buildMenuCallback){
        $.post('/vocabInLearning', { vocab: $('a', this).text() }, function(data) {
          var isLearnt = (data === '1');

          buildMenuCallback({
            items: {
              addToLearning: {
                name: "Add vocab to learning",
                visible: function(key, opt){
                  return !isLearnt;
                },
                callback: function(key, opt){
                  $.post('/addVocabToLearning', { vocab: $('a', this).text() }, function(data) {
                    if(data !== '1'){
                      alert('Adding vocab to learning failed.');
                    } else {
                      alert('Added vocab to learning');
                    }
                  });
                }
              },
              removeFromLearning: {
                name: "Remove vocab from learning",
                visible: function(key, opt){
                  return isLearnt;
                },
                callback: function(key, opt){
                  $.post('/removeVocabFromLearning', { vocab: $('a', this).text() }, function(data) {
                    if(data !== '1'){
                      alert('Remove vocab from learning failed.');
                    } else {
                      alert('Removed vocab from learning');
                    }
                  });
                }
              }
            }
          });
        });
      }

      $trigger.data('buildMenu', buildMenu);

      return $trigger.data('buildMenu')();
    }
  });

  $('#sentences').contextMenu({
    selector: ".entry",
    build: function($trigger, e) {
      e.preventDefault();

      function buildMenu(){
        $.post('/sentenceInLearning', { vocab: $('a', this).text() }, function(data) {
          var isLearnt = (data === '1');

          return {
            items: {
              addToLearning: {
                name: "Add sentence to learning",
                visible: function(key, opt){
                  return !isLearnt;
                },
                callback: function(key, opt){
                  $.post('/addSentenceToLearning', { vocab: $('a', this).text() }, function(data) {
                    if(data !== '1'){
                      alert('Adding sentence to learning failed.');
                    } else {
                      alert('Added sentence to learning');
                    }
                  });
                }
              },
              removeFromLearning: {
                name: "Remove sentence from learning",
                visible: function(key, opt){
                  return isLearnt;
                },
                callback: function(key, opt){
                  $.post('/removeSentenceFromLearning', { vocab: $('a', this).text() }, function(data) {
                    if(data !== '1'){
                      alert('Remove sentence from learning failed.');
                    } else {
                      alert('Removed sentence from learning');
                    }
                  });
                }
              }
            }
          }
        });
      }

      $trigger.data('buildMenu', buildMenu);

      return $trigger.data('buildMenu')();
    }
  });