title: When are props updated in the VueJS lifecycle
body: <p>I am trying to access a prop in the mounted hook of the vuejs lifecycle but it doesn't seem to have any value</p>
  
  <p>My (really simplified) component looks like this:</p>
  
  <pre><code>export default {
      props: [
          'columns',
      ],
      mounted: function() {
          console.log(this.columns)
      }
  }
  </code></pre>
  
  <p>The parent looks like this:</p>
  
  <pre><code>&lt;script&gt;
      import DatatableHeader from './DatatableHeader.vue';
  
      export default {
          data: {
              columns: [{'heading': 'Column 1'}, {'heading': 'Column 2'}]
          },
          components: {
              'datatableheader'   : DatatableHeader,
          }
      }
  &lt;/script&gt;
  </code></pre>
  
  <p>The component renders correctly but the output from the mounted function is an empty array, it seems like  timing issue to me.</p>
  
  <p>Am I doing something wrong? Or is there a different lifecycle hook that I should use.</p>
  
  <p>Thanks!</p>