Marionette.js collection is undefined in collection view

Question

I am fairly new with Marionette.js and seem to be having some trouble rendering a Collection View.

I am receiving the following console error message when trying to show the view: Uncaught TypeError: Cannot read property 'toJSON' of undefined.

It seems that the collection is not binding to the child view. The instance of the Collection View looks OK, meaning I see the childView property and the collection property with the fetched models. The docs seem pretty straightforward on how to construct a collection view so not sure what I'm missing. Thanks.

Child view:
var UserProfile = Marionette.ItemView.extend({
  template: '',
  initialize: function() {
    this.template = Marionette.TemplateCache.get("#userprofile");
  },
  render: function() {
    console.log(this.collection); //undefined
    var data = this.collection.toJSON(); //error message here
    this.$el.html(this.template({data:data}));
  } 
});

//Collection view:
var UserView = Marionette.CollectionView.extend({  
  childView: UserProfile
});

// Fetch collection and show:
var myQuery = new Parse.Query(app.Models.User);
myQuery.limit(200).containedIn(option, uiArray);

var Contacts = Parse.Collection.extend({
  model: app.models.User,
  query: myQuery
});

var contacts = new Contacts();
contacts.fetch().then(function(contacts) {
  var userview = new UserView({collection:contacts});
  app.regions.get("content").show(userview);
})

Answer 1

You are asking a "collection" in an ItemView. ItemView operates with an item. So it make sense to write something like this:

render: function() {
    console.log(this.model); //undefined
    var data = this.model.toJSON(); //error message here
    this.$el.html(this.template({data:data}));
    }   
});