postal.js/example/node/client/js/models/menu-model.js

define( [
	'backbone',
	'bus'
],
	function( Backbone, bus ) {
		"use strict";

		return Backbone.Model.extend({
			defaults: {
				sessionId: "",
				searchOwnership: "",
				searchTerm: "",
				requests: false
			},

			initialize: function() {
				_.bindAll( this );
				this.subscriptions = [
					bus.app.subscribe( "search.info", this.setCurrentSearch ).defer(),
					bus.app.subscribe( "search.new.ask", this.updateReqCount).defer(),
					bus.app.subscribe( "search.requests", this.updateReqCount ).defer()
				];
				bus.app.publish({
					topic: "get.search.info",
					data: {}
				});
			},

			dispose: function(){
				_.each( this.subscriptions, function( subscription ){
					subscription.unsubscribe();
				});
				this.clear( { silent: true } );
			},

			setCurrentSearch: function( data, env ) {
				var self = this;
				self.set( "searchTerm", data.searchTerm );
				postal.utils.getSessionId(
					function( session ) {
						self.set( "sessionId", session.id, { silent: true } );
						self.set( "searchOwnership",
							(session.id === data.id)
								? "You own the search."
								: "You do not own the search."
						);
					}
				);
			},

			updateReqCount: function( data, env ) {
				if((_.isArray(data) && data.length) || data.searchTerm) {
					this.set("requests", true);
				}
				else {
					this.set("requests", false);
				}
				this.change("requests");
			}
		});
	});