JSFiddle - React, Tailwind, and code Playground

by pxfunc

HTML

<div id="container"></div>

CSS

.trans {
    width: 20px;
    height: 20px;
    background-color: cyan;
    -webkit-transition: all 5s ease;
       -moz-transition: all 5s ease;
        -ie-transition: all 5s ease;
         -o-transition: all 5s ease;
            transition: all 5s ease;
}
.wide {
    width: 200px;
}

JavaScript

var div = $('<div class="trans" />');
$('#container').append(div);
setTimeout(function() {div.addClass('wide')}, 1);