JSFiddle - React, Tailwind, and code Playground

HTML

<div class="column">
<ul class="list">
<li class="item">item 1</li>
<li class="item">item 2</li>
<li class="item">item 3</li>
</ul>
</div>
<div class="column">
<ul class="list">
<li class="item">item 4</li>
<li class="item">item 5</li>
</ul>
</div>
<div class="column">
<ul class="list">
<li class="item">item 6</li>
</ul>
</div>

JavaScript

$('.list').each(function(){
var $this = $(this);
var items = $this.find('.item').length;
$this.closest('.column').append(items);
})