title: Typo3 list children of a specific system category (news extension)
body: <p>I have a system category tree in Typo3:</p>
  <pre><code>─┬─A─┬─A1
   │   └─A2
   │
   └─B─┬─B1
       ┼─B2
       └─B3
  </code></pre>
  <p>I want to render the children of B tree.</p>
  <p>On each child news item I am able to get the categories in a string on every iteration</p>
  <pre><code>&lt;f:for each=&quot;{news}&quot; as=&quot;newsItem&quot; iteration=&quot;iterator&quot;&gt;
    &lt;!-- render partial=&quot;List/ServiceItem&quot; --&gt;
    &lt;div
      &lt;f:if condition=&quot;{newsItem.categories}&quot;&gt;
          data-groups=&quot;[&lt;f:for each=&quot;{newsItem.categories}&quot; s=&quot;category&quot; iteration=&quot;iteratorCategories&quot;&gt;'{category.title}'&lt;f:if condition=&quot;{iteratorCategories.isLast}&quot;&gt;&lt;f:then&gt;&lt;/f:then&gt;&lt;f:else&gt;,&lt;/f:else&gt;&lt;/f:if&gt;&lt;/f:for&gt;]&quot;
      &lt;/f:if&gt;
    &gt;{newsItem.title} &amp; other stuff&lt;/div&gt;
  &lt;/f:for&gt;
  </code></pre>
  <p>I am using Shuffle.js to filter the list and I need all the B - tree children to create the group control
  I tried this:</p>
  <pre><code>&lt;div class=&quot;news-list-category&quot;&gt; categories:
    &lt;f:for each=&quot;{categories}&quot; as=&quot;category&quot; iteration=&quot;iteratorCategories&quot;&gt;
      &lt;f:if condition=&quot;{category.title} == 'B'&quot;&gt;
        {category.title}
         &lt;f:debug&gt;{category.children}&lt;/f:debug&gt;
         &lt;f:if condition=&quot;{category.children}&quot;&gt;
              children:
              &lt;f:for each=&quot;{category.children}&quot;
                        as=&quot;subCategory&quot;
                         iteration=&quot;iteratorSubCategories&quot;&gt;
                   &lt;span&gt;{subCategory.title}&lt;/span&gt;
               &lt;/f:for&gt;
            &lt;/f:if&gt;
       &lt;/f:if&gt;
    &lt;/f:for&gt;
  &lt;/div&gt;
  </code></pre>
  <p><code>category.children</code> and <code>category.item.children</code>
  returns null</p>
  <p><code>&lt;f:if condition=&quot;{category.title} == 'B'&quot;&gt;</code>
  gets to the correct first level item</p>
  <p>I used
  <code>typo3conf/ext/news/Resources/Private/Templates/Styles/Twb/Templates/Category/List.html</code></p>
  <p>as a reference as well</p>
  <p>Should I rather do this in typoscript and pass to fluid</p>
  <pre><code> &lt;f:cObject typoscriptObjectPath=&quot;lib.myTyposSubCategoryList&quot; /&gt;
  </code></pre>
  <p>I'll go and see if I can get Typoscript to render this but would like a fluid solution</p>
  <p>Thanks</p>