title: Update var using .change?
body: <p>I have an important question that I'm starting to face on 80% of the cases.</p>
  
  <p>Lets say I have this:</p>
  
  <pre><code>var bcount = properties.count;
  favicon.badge(bcount);
  bcount.change(function() { favicon.badge(bcount); });
  </code></pre>
  
  <p><code>properties.count</code> = its a number that changes depending on the user actions.
  <code>favicon.badge</code> its a javascript that shows the action, which is working good.</p>
  
  <p>I tried to use .change on the bcount var, but is giving me error as I supposed because is not an element.
  Is there any way to listen a var when value changes?</p>
  
  <p>The problem I'm facing is that when the count gets updated, with a new number. It only updates after refreshing the page.</p>
  
  <p>Thanks!!</p>
  
  <p>Edit: I'm trying to setup getter and stter:</p>
  
  <pre><code>var bcount = {
    a: properties.count,
    get b() { 
      return this.a;
    },
    set c(cname) {
      this.a;
    }
  };
  </code></pre>
  
  <p>Is that okay? And now how i can init the call?</p>