JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://builds.emberjs.com/handlebars-1.0.0-rc.4.js"></script>
<script src="http://builds.emberjs.com/ember-1.0.0-rc.6.js"></script>
<link rel="stylesheet" href="http://netdna.bootstrapcdn.com/twitter-bootstrap/2.3.2/css/bootstrap-combined.min.css">
<script type="text/x-handlebars" data-template-name="index">
    
    <div>{{computedProp}}</div>
    
    <!-- This will cause an error:
        {{computedProp}}
    This is because Ember.Handlebars will still bind expressions even if they are enclosed in HTML comments. -->
    
    {{!-- This will not cause an error:
        {{computedProp}}
    This is because it is a Handlebars comment, which Ember.Handlebars knows to process without binding expressions. --}}
    
    <div class="btn btn-danger" {{action recomputeProp}}>Recompute</div>
    
    <div>Clicking the button above will cause computedProp to be recomputed. When this happens, Ember tries to propegate the change into the DOM, but the HTML comment in the template causes an error to be thrown.</div>
    
    <div>In many cases, this will completely break an app.</div>
    
</script>

JavaScript

App = Em.Application.create();

App.IndexController = Em.ObjectController.extend({
    text: 'Data binding throws an error if a Handlebars expression is enclosed in an HTML block comment.',
    
    computedProp: function() {
        return 'This is a computed property: ' + this.get('text');
    }.property('text'),
    
    recomputeProp: function() {
        this.set('text', 'I have been changed! ' + this.get('text'));
    }
});