JSFiddle - React, Tailwind, and code Playground

HTML

<div></div>

CSS

div {
    width: 50px;
    height: 50px;
    background-color: red;
    transition: all 1s;
}
div:hover {
    width: 100px;
    height: 100px;
    background-color: blue;
}

JavaScript

document.querySelector('div').addEventListener('transitionend', function () {
    this.style.backgroundColor = 'green';
});