What's wrong with my jQuery code finding the first parent?

Question

I'm developing a small app which haves a tree view menu, so this is the html:

<ul class="sidebar-menu">
    <li class="active"><a href="javascript:;"> ELEMENT 1 </a></li>
    <li class="treeview">
        <a href="javascript:;"> ELEMENT 2 <span class="pull-right-container"><i class="fa fa-angle-left pull-right"></i></span></a>
        <ul class="treeview-menu">
            <li><a href="javascript:;"> ELEMENT 2.1 </a></li>
            <li><a href="javascript:;"> ELEMENT 2.2 </a></li>
        </ul>
    </li>
    <li><a href="javascript:;"> ELEMENT 3 </a></li>
</ul>

I'm trying to highlight the clicked li element adding the .active class to it. But, when you click on a subelement, I want to highlight also the parent. For example, if you click the ELEMENT 2.1 I want to highlight also the ELEMENT 2.

This is my jQuery code to get, first the clicked element, and then it's li parent (I can't do ir without the :not selector for other reasons:

$(".sidebar-menu").on("click", "li:not(.treeview)", function(e){
    $(e.delegateTarget).parents("li").first();
}

The if statement works as expected, but the second line always give me a undefined error in the console.

Answer 1

Working Fiddle.

You could use the jQuery object $(this) that refer to the current clicked element then addClss() to add class active class :

$(this).parents('li').addClass('active');

NOTE : you have to use $('li').removeClass('active'); to remove active class from all the other li's`.

Hope this helps.

$(".sidebar-menu").on("click", "li:not(.treeview)", function(e){
  //remove active class from all the other li's
  $('li').removeClass('active');
 
  $(this).addClass('active'); //add active class to the clicked li

  //Add active class to the parent if exist
  if( $(this).parents('li').length > 0)
      $(this).parents('li').addClass('active');
})

.active{
  background-color: yellow;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<ul class="sidebar-menu">
  <li class="active"><a href="javascript:;"> ELEMENT 1 </a></li>
  <li class="treeview">
    <a href="javascript:;"> ELEMENT 2 <span class="pull-right-container"><i class="fa fa-angle-left pull-right"></i></span></a>
    <ul class="treeview-menu">
      <li><a href="javascript:;"> ELEMENT 2.1 </a></li>
      <li><a href="javascript:;"> ELEMENT 2.2 </a></li>
    </ul>
  </li>
  <li><a href="javascript:;"> ELEMENT 3 </a></li>
</ul>