Iron Router subscription loading pattern

gistfile1.js

// Global data controller

DataController = RouteController.extend({
  onBeforeAction: function(pause) {
    
    var loading = false, notFound = false;
    _.each(this.routeData(), function (dataItem) {

      var handle = dataItem.subscription;
      
      if (dataItem.wait && ! dataItem.cursor.count()) {
          if (handle.ready()) {
              notFound = true;
          } else {
              loading = true;
          }
      }
    });
    
    // Case 1: not found
    if (notFound) {
        this.render('notFound');
        return pause();
    }
    // Case 2: still loading
    if (loading) {
        this.render('loading');
        return pause(); // (or use else if)
    }
    // Case 3: proceed to route
    
  },
  data: function() {
    var data = {};
    _.each(this.routeData(), function (dataItem) {
      data[dataItem.name] = dataItem.cursor;
    });
    return data;
  }
});


PostPageController = DataController.extend({
  routeData: function() {
    return [
      {
        name: 'post',
        subscription: Meteor.subscribe('singlePost', this.params._id),
        cursor: Posts.findOne(this.params._id),
        persist: true, //  Subscription Manager style subscription persistence?
        wait: true
      },
      {
        name: 'postComments',
        subscription: Meteor.subscribe('postComments', this.params._id),
        cursor: Comments.find({postId: this.params._id, parentCommentId: null}, {sort: {score: -1, postedAt: -1}}),
        wait: false
      },
      {
        name: 'postUsers',
        subscription: Meteor.subscribe('postUsers', this.params._id),
        wait: false
      }
    ]
  }
});