Using Event Listeners to create observer pattern

gistfile1.js

// Custom Events Used:
// { type: "privateMessages_newConversation", messages: {}, partner: {} }
// { type: "privateMessages_newMessage", message: {} }
// { type: "privateMessages_conversationListLoaded", payload: {} }

var PrivateConversation = function(event_id, recipient_hash, url) {
  this.partner = recipient_hash;
  this.event_id = event_id;
  this.messager_id = recipient_hash.messager_id;
  this.messager_type = recipient_hash.messager_type;
  this.url = url;
};
_.extend(PrivateConversation.prototype, PP.mixins.JsonRequest); //attach mixins before main functions so functions can override if needed

_.extend(PrivateConversation.prototype, {
  getMessages: function() {
    var that = this;
    this.getJSON({ 'event_id': this.event_id, 'messager_id': this.partner.messager_id, 'messager_type': this.partner.messager_type }, 'GET', 
      function(response){
        that.messages = response.private_messages;
        $.event.trigger({ type: "privateMessages_newConversation", messages: that.messages, partner: that.partner });
      });
  }
}

var ConversationView = function(options) {
  var that = this;
  $(document).on("privateMessages_newConversation", function(e){
    that.messages = e.messages;
    that.partner = e.partner;
    that.render();
  });
};

My only feedback here would be that since jQuery's event system allows you to namespace events (with a dot, I think), you should use that. This allows listeners to listen by namespace in addition to listening for specific events.

So instead of

// { type: "privateMessages_newConversation", messages: {}, partner: {} }
// { type: "privateMessages_newMessage", message: {} }
// { type: "privateMessages_conversationListLoaded", payload: {} }

we would have

// { type: "newConversation.privateMessages", messages: {}, partner: {} }
// { type: "newMessage.privateMessages", message: {} }
// { type: "conversationListLoaded.privateMessages", payload: {} }

that does look better, the problem is, if someone somewhere does
$(document).on( "newConversation", function(e){...} );
they will get all the actions intended for "newConversation.privateMessages"

@akahn what do you think about the trade off here?

@raphaeleidus, isn't that the idea? Listeners can subscribe to all 'newMessage' events or only the ones within the 'privateMessages' namespace.