JSFiddle - React, Tailwind, and code Playground

HTML

<div class="lightOn"></div>
<div class="lightOff"></div>

CSS

.lightOn {
    height: 90px;
    width:90px;
    background-color:yellow;
    border-radius: 100%;
    float:left;
    margin:10px;
}
.lightOff {
    height: 90px;
    width:90px;
    background-color:grey;
    border-radius: 100%;
    float:left;
    margin:10px;
}

JavaScript

$('.lightOn').click(function() {
    $(this).removeClass('lightOn');
    $(this).addClass('lightOff');
});
$('.lightOff').click(function() {
    $(this).removeClass('lightOff');
    $(this).addClass('lightOn');
});