title: How do I figure out the setup of composition api?
body: <p>What does setup function's <code>return</code> value do?</p>
  <pre><code>const Comp = defineComponent({
      props: {
          count: {
            default: 0
          }
      },
      setup(props) {
          return () =&gt; props.count;
      }
  })
  </code></pre>