ember.js - Controller not seeing the updated model - asynchronous handling -

i have simple requirement many things in ember.js, i'm banging head against wall trying implemented.

i have overview screen couple of records displayed in table.

to render overview screen i'm using following route

app.locationsindexroute = ember.route.extend({    setupcontroller: function(controller) {     var locations = app.location.find();     controller.set('content', locations);   },    rendertemplate: function() {     this.render('locations.index',{into:'application'});   }  }); 

this working fine. conditionally render overviewtable.

• if records present render table.
• if no records present display message.

i tried implementing using following controller.

app.locationsindexcontroller = ember.arraycontroller.extend({   locationspresent: function() {     var model = this.get('content');     return model.content.length > 0;   }.property() }); 

and following template

{{#if locationspresent}}    <table class="table table-hover">   <tr>     <th>latitude</th>     <th>longitude</th>     <th>accuracy</th>     <th></th>     <th></th>   </tr>     {{#each location in model}}       <tr>       <td>{{location.latitude}}</td>       <td>{{location.longitude}}</td>       <td>{{location.accuracy}}</td>       <td>{{#linkto locations.edit location}}edit{{/linkto}}</td>       <td><button {{action removeitem location}}>delete</button></td>       </tr>     {{/each}}   </table>  {{else}}   no locations present. {{/if}} 

the computed locationspresent property called once, before page rendered. @ time assume model still being loaded length = 0.

when page rendered, locations app.locations.find() available locationspresent not called anymore, meaning page decided render no locations present. message.

i went through managing asyncrony in ember page , assumed computer property locationspresent updated if underlying model changed (if loaded) page states :

using computed property author eliminated need explicitly invoke computation in callback when underlying property changed.

i'd love know i'm doing wrong , how can fix more importantly why seem missing of these core concepts of ember.js. if can point me in docs / guides explained i'd love know.

i think easy fix. need add property observing. so:

locationspresent: function() {   var length = this.get('content.length');   return length > 0; }.property('content.@each') 

adding @each necessary if locationspresent needs recalculate wen content added. think can observe 'content.isloaded'