title: Charts.js with vue not drawing charts after fetching data
body: <p>This is how json response looks like <code>[[61,57,34],[1,1,3]]</code> 
  I want to use the first array for labels and the second for data.</p>
  
  <p>If I set <code>labels and data</code> inside <code>app</code> manually it works though.</p>
  
  <p>eg
  <code>labels: ["q", "w", "e"]</code>
  <code>data: [1, 5, 10]</code></p>
  
  <pre><code>Vue.component('chart', {
    props: ['labels', 'data', 'type'],
    template: `
      &lt;canvas style="width: 512px; height: 256px"&gt;&lt;/canvas&gt;
    `,
    mounted: function () {
      new Chart(this.$el, {
        type: this.type,
        data: {
            labels: this.labels,
            datasets: [{
                label: '# of Votes',
                data: this.data,
                borderWidth: 1
            }]
        },
        options: {
            scales: {
                yAxes: [{
                    ticks: {
                        beginAtZero:true
                    }
                }]
            }
          }
        })
    }
  });
  
  new Vue({
    el: '#app',
    data: {
      message: "test",
      labels: [],
      data: []
    },
    methods: {
      fetchData: function() {
        this.$http.get('/admin/fetch_data').then(res =&gt; {
          this.labels = res.body[0];
          this.data = res.body[1];
        })
      }
    },
    beforeMount() {
      this.fetchData()
    }
  });
  </code></pre>
  
  <p>component on page</p>
  
  <pre><code>&lt;div id="app"&gt;
    {{message}}
    &lt;chart :labels="labels" :data="data" type="bar"&gt;&lt;/chart&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>The data seems to be loaded but there're no chart bars on page.</p>
  
  <p><a href="https://i.stack.imgur.com/jutnG.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jutnG.png" alt="enter image description here"></a></p>