title: Vue3 Check if a Slot is Empty
body: <p>Is there a Vue3 equivalent to the following Vue2 method:</p>
  <pre class="lang-js prettyprint-override"><code>methods: {
     hasSlot(name) {
        return !!this.$slots[name]
     }
  }
  </code></pre>
  <p>in Vue3's Composition API?</p>
  <p>I've tried:</p>
  <pre class="lang-js prettyprint-override"><code>setup({slots}) {
     const hasSlot = (name) =&gt; {
        return !!slots[name];
     }
  
     return { hasSlot }
  
  }
  </code></pre>
  <p>but it isn't returning the expected value as <code>slots</code> is undefined (per error out in console).</p>