JSFiddle - React, Tailwind, and code Playground

get nearest element above with class

by IllusionMH

HTML

<ul>
    <li class="contentBlock">1 content</li>
    <li>1</li>
    <li class="contentBlock">2 content</li>
    <li>2</li>
    <li class="contentBlock">3 content</li>
    <li>3</li>
    <li class="contentBlock">4 content</li>
    <li>4</li>
    <li class="contentBlock">5 content</li>
    <li>5</li>
    <li class="contentBlock">6 content</li>
    <li>6</li>
    <li class="contentBlock" id="tst">7 content</li>
    <li>7</li>
    <li class="contentBlock">8 content</li>
    <li>8</li>
    <li class="contentBlock">9 content</li>
    <li>9</li>
    <li class="contentBlock">10 content</li>
    <li>10</li>
</ul>

CSS

#tst {
    background: green;
}
.active {
    background: red;
}

JavaScript

$('#tst').prevAll('.contentBlock').first().addClass('active')