title: [Vue]How to use slot-scope in Loop Component
body: <p>I design a tree component,use the loop component to show the leaf relation.The problem occured when I want to modify the label to show pic or icon.<br>
  Like this.</p>
  
  <pre><code>&lt;img ...&gt;1
  &lt;icon ...&gt;2
  </code></pre>
  
  <p>But I don't know how to use slot-scope in Loop Component.</p>
  
  <pre><code>component:'tree':
  &lt;template&gt;
      &lt;ul&gt;
          &lt;li&gt;
              ...
              &lt;slot :data='data'&gt;
              &lt;/slot&gt;
              ...
              &lt;tree ....&gt;
                  &lt;slot&gt;&lt;!--How to show the slot???--&gt;&lt;/slot&gt;
              &lt;/tree&gt;
          &lt;/li&gt;
      &lt;/ul&gt;
  &lt;/template&gt;
  </code></pre>
  
  <p>If use <code>&lt;slot :data='data'&gt;&lt;/slot&gt;</code> in tree,it only shows the parent node(level 1).Like this</p>
  
  <pre><code>&lt;img ...&gt;1
      &lt;img ...&gt;1  (there should be 1-1)
      &lt;img ...&gt;1  (there should be 1-2)   
  &lt;img ...&gt;2
  </code></pre>
  
  <p>If use <code>&lt;slot :data='data.children'&gt;&lt;/slot&gt;</code>,it must throw exception.<br>
  Can I use the slot-scope in loop component?If Don't use loop,how to show the relation?<br>
  If anyone can give me some help,thanks.</p>