JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/dot-luv/jquery-ui.css">
<div class="item">1</div>
<div class="item">2</div>
<div class="item">3</div>
<div class="item">4</div>
<div class="item">5</div>
<div class="item">6</div>
<div class="item">7</div>
<div class="item">8</div>

CSS

ul { border: solid 1px #ccc; padding: 20px; }
li { border: solid 1px #ddd; }

JavaScript

var elems = $("div.item");
for(var i = 0; i < elems.length; i+=5) {
  elems.slice(i, i+5).wrap('<li></li>').parent().wrapAll("<ul></ul>");
}