JSFiddle - React, Tailwind, and code Playground

HTML

<ul id="sortable1" class="connectedSortable">
<li class="ui-state-default">Item 1</li>
<li class="ui-state-default">Item 2</li>
<li class="ui-state-default">Item 3</li>
<li class="ui-state-default">Item 4</li>
<li class="ui-state-default">Item 5</li>
</ul>

JavaScript

var sortable1 = document.getElementById("sortable1").children;
var array = new Array();
for(i=0; i<sortable1.length; i++) {
    array.push(sortable1[i].innerHTML);
}
alert(array);