title: How to order comments based on parent/child relationship
body: <p>I have comments component, which renders comments. I can reply to a comment and it is stored as a child (parentId!=null and parentId=commentId);
  In my reducer I would like to take this into account and display comments in hierarchical order, e.g.</p>
  
  <ol>
  <li>comment1
  
  <ol start="3">
  <li>comment3 parentid1</li>
  </ol></li>
  <li>comment2
  
  <ol start="5">
  <li>comment5</li>
  <li>comment6</li>
  </ol></li>
  </ol>
  
  <p>So far I did as follows, but it does not work:</p>
  
  <pre><code>if (action.comment.parentId) {
                      let index = state.requestComments.findIndex(item =&gt;
                          item.id === action.comment.parentId);
                       return {
                          ...state,
                          requestComments: [...state.requestComments.slice(
                              0, index),
                          action.comment,
                          ...state.requestComments.slice(index)
                          ],
                          error: null,
                          isCommentLoading: false
                      };
                  } else {
                      return {
                          ...state,
                          requestComments: [...state.requestComments,
                          action.comment],
                          error: null,
                          isCommentLoading: false
                      };
                  }
  </code></pre>