meteor__microscope/client/templates/posts/post_item.js

Template.postItem.helpers({
  ownPost: function ()  {
    // Template is invoked in the context of a Post, so 'this' is a Post.
    return this.userId === Meteor.userId();
  },

  domain: function () {
    var a = document.createElement('a');
    a.href = this.url;
    return a.hostname;
  },

  upvotedClass: function () {
    var userId = Meteor.userId();
    if (userId && !_.include(this.upvoters, userId)) {
      return "btn-primary upvotable";
    } else {
      return "disabled";
    }
  }
});

Template.postItem.events({
  'click .upvotable': function (e) {
    e.preventDefault();
    Meteor.call('upvote', this._id);
  }
});