title: Create a countdown with vue.js and moment.js
body: <p>I am creating a timer using vue.js and moment.js, I use only minutes and seconds, my code should work, but I do not get the desired result:</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>var app = new Vue({
    el: '#app',
    data: {
      date: moment(60 * 10 * 1000)
    },
    computed: {
      time: function(){
        return this.date.format('mm:ss');
      }
    },
    mounted: function(){
      var aa = this.date;
      
      setInterval(function(){
        aa.subtract(1, 'seconds');
      }, 1000);
    }
  });</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;script src="https://momentjs.com/downloads/moment.js"&gt;&lt;/script&gt;
  &lt;script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.min.js"&gt;&lt;/script&gt;
  
  &lt;div id="app"&gt;{{ time }}&lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>