Vulcan/packages/telescope-posts/lib/client/templates/post_item.js

Template.post_item.helpers({
  postClass: function () {
    var post = this;
    var postClass = "post ";
    
    postClass += "author-"+Telescope.utils.slugify(post.author)+" ";

    if (this.sticky) {
      postClass += "sticky ";
    }
    postClass = Telescope.callbacks.run("postClass", postClass, post);
    return postClass;
  }
});