JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://github.com/downloads/emberjs/ember.js/ember-0.9.5.min.js"></script>
<script type="text/x-handlebars" data-template-name="test">
  {{style.a}}
</script>

JavaScript

test = Em.View.create({
    
    templateName: "test",
    
    style : Ember.Object.create({
        a:4,
        b:2
    }),
    setStyle : function(key, val){
        var style = this.get('style');
        style[key] = val;
        this.set('style', style);        
    },
}).append();

test.addObserver('style', function() {
  alert("here");
});

test.setStyle("a", 6);