我写的这段把对象数据变为DOM节点的代码该怎么优化？

function Activity(obj) {

  var activityCOntent= document.createElement('a');

  activityContent.innerHTML = obj.post.c;

  activityContent.className = 'activity-content';

  activityContent.style.overflow = 'hidden';

  activityContent.href = '/t/'+obj.tid+'#'+obj.pid;

  var activityTitleText = document.createElement('span');

  activityTitleText.innerHTML = obj.oc.t;

  activityTitleText.style.overflow = 'hidden';

  var activityTitle = document.createElement('div');

  activityTitle.className = 'activity-title';

  var activityTitleA = document.createElement('a');

  activityTitleA.appendChild(activityTitleText);

  activityTitleA.href = '/t/'+obj.tid;

  var activityInfo = document.createElement('span');

  activityInfo.className = 'activity-info';

  if(obj.forum) {

    var color = obj.forum.color || 'orange';

    var forum = document.createElement('a');

    forum.href= '/f/'+obj.fid;

    var forumText = document.createElement('span');

    forumText.className = 'activity-title-forum';

    forumText.style.backgroundColor = color;

    forumText.innerHTML = ' '+obj.forum.abbr+' ';

    forum.appendChild(forumText);

    activityTitle.appendChild(forum);

  }

  if(obj.toMyForum) {

    var color = obj.toMyForum.color || 'orange';

    var toMyForum = document.createElement('a');

    toMyForum.href= '/m/'+obj.toMyForum._key;

    var toMyForumText = document.createElement('span');

    toMyForumText.className = 'activity-title-forum';

    toMyForumText.style.backgroundColor = color;

    toMyForumText.innerHTML = ' '+obj.toMyForum.abbr+' ';

    toMyForum.appendChild(toMyForumText);

    activityTitle.appendChild(toMyForum);

  }

  if(obj.myForum) {

    var color = obj.myForum.color || 'orange';

    var myForum = document.createElement('a');

    myForum.href= '/m/'+obj.myForum._key;

    var myForumText = document.createElement('span');

    myForumText.className = 'activity-title-forum';

    myForumText.style.backgroundColor = color;

    myForumText.innerHTML = ' '+obj.myForum.abbr+' ';

    myForum.appendChild(myForumText);

    activityTitle.appendChild(myForum);

  }

  activityTitle.appendChild(activityTitleA);

  activityInfo.appendChild(activityTitle);

  activityInfo.appendChild(activityContent);

  var activityUser = document.createElement('div');

  activityUser.className = 'activity-user';

  activityUserA = document.createElement('a');

  activityUserA.href = '/activities/'+obj.uid;

  var activityUserAvatar = document.createElement('img');

  activityUserAvatar.className = 'activity-user-avatar';

  activityUserAvatar.src = '/avatar/'+ obj.uid;

  activityUserA.appendChild(activityUserAvatar);

  var username = document.createElement('a');

  username.href = '/activities/'+obj.uid;

  username.innerHTML = obj.user.username;

  activityUser.appendChild(activityUserA);

  activityUser.appendChild(username);

  var type;

  switch (obj.type) {

    case 1:

      type = 'Po';

      break;

    case 2:

      type = 'Re';

      break;

    case 4:

      type = 'Rc';

      break;

    default:

      type = 'X';

  }

  var activityType = document.createElement('div');

  activityType.className = 'activity-type';

  var activityTypeText = document.createElement('div');

  activityTypeText.className = 'activity-type-text';

  activityTypeText.innerHTML = type;

  var activityTypeDate = document.createElement('div');

  activityTypeDate.className = 'activity-type-date';

  activityTypeDate.innerHTML = moment(obj.time).fromNow();

  activityType.appendChild(activityTypeText);

  activityType.appendChild(activityTypeDate);

  var activity = document.createElement('div');

  activity.className = 'activity';

  activity.appendChild(activityType);

  activity.appendChild(activityUser);

  activity.appendChild(activityInfo);

  return activity;

}