JSFiddle - React, Tailwind, and code Playground
HTML
<div class="xyz">123</div>
<div class="add">ADD</div>
<div class="xyz">sadasd</div>
<div class="add">ADD</div>
<div class="xyz">123</div>
<div class="add">ADD</div>
CSS
.long {
background :#000;
color : #fff;
}
JavaScript
$('div.xyz:contains("123")').each(function(){
$(this).next(".add").addClass("long");
})