title: How does a single file component pass context.data?
body: <p>I loop functional components in the <code>transition-group</code>, and because I didn't pass a key reference to the root element of the tag component to the tag component.</p>
  
  <p>But how does a single file component pass the <code>context.data</code>?</p>
  
  <p>The sample link
  <a href="https://codesandbox.io/s/rjjmpvwm4n/" rel="nofollow noreferrer">https://codesandbox.io/s/rjjmpvwm4n/</a></p>
  
  <p><a href="https://github.com/vuejs/vue/issues/7777" rel="nofollow noreferrer">https://github.com/vuejs/vue/issues/7777</a></p>