JSFiddle - React, Tailwind, and code Playground

HTML

<button class="follow_btn btn btn-success" value="1">Follow</button>

CSS

.btn {
    padding:1em;
}
.btn-success {
    background:green;
}
.btn-danger {
    background:red;
}

JavaScript

$('.follow_btn').on("click", function () {
    $(this).toggleClass('unfollow_btn follow_btn').toggleClass('btn-danger btn-success')
});