JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//cdnjs.cloudflare.com/ajax/libs/handlebars.js/1.1.2/handlebars.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/ember.js/1.3.1/ember.js"></script>
<script>
    App = Ember.Application.create();

    App.ApplicationController = Ember.ObjectController.extend({
        inValue: 0,
        outValue: function() {
            if (!(arguments.length > 1)) {
                var inValue = this.get('inValue');
                if (!isNaN(inValue) && isFinite(inValue)) {
                    return 2 * inValue
                } else {
                    return '???'            
                }
            }    
        }.property('inValue')    
    });
</script>

<script type="text/x-handlebars">
    <p>{{view Ember.TextField valueBinding="inValue"}}</p>
    <p>{{view Ember.TextField valueBinding="outValue"}}</p>
</script>