JSFiddle - React, Tailwind, and code Playground

HTML

<a title="WIFI" href="javascript: void(0)" id="showWifi_${item.index}" class="showWifi">
    <div class="news_box news_box_01 hvr-underline-from-center " style="margin-right: 50px;">
        This is div1
    </div>
    <div>This is div2</div>
          <div>This is div3</div>
        <div>This is div4</div>
</a>

CSS

.testDiv{
    background-color : green;    
}

JavaScript

$(function () {
    $(".showWifi").find("div").first().addClass("testDiv");
})