JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
    <li id="one">item 1</li>
    <li id="two">item 2</li>
    <li id="three">item 3</li>
    <li id="four">item 4</li>
</ul>

<table>
    <tbody>
        <tr id="one">
            <td>1</td>
            <td>item 1</td>
        </tr>
        <tr id="two">
            <td>2</td>
            <td>item 2</td>
        </tr>
        <tr id="three">
            <td>3</td>
            <td>item 3</td>
        </tr>
        <tr id="four">
            <td>4</td>
            <td>item 4</td>
        </tr>        
    </tbody>
</table>

JavaScript

$("ul").sortable({
    update:function(ev,ui){
        console.log(ui.item[0].previousElementSibling);
        console.log(ui.item[0].nextElementSibling);
    }
});

$("tbody").sortable({
    update:function(ev,ui){
        console.log(ui.item[0].nextElementSibling);
        console.log(ui.item[0].previousElementSibling);
    }
});