JSFiddle - React, Tailwind, and code Playground

by Jonny

HTML

<textarea class="tweet-box"></textarea>

CSS

.tweet-box {
    height: 1em;
    width: 100%;
    padding: 5px;
    transition: height 250ms ease-in-out;
}

.tweet-box--expanded {
    height: 4em;
}

JavaScript

var tweet_box = $('.tweet-box' );

tweet_box.focus( function (e) {
	$(this).addClass( 'tweet-box--expanded' );
});

tweet_box.blur( function(e) {
	$(this).removeClass( 'tweet-box--expanded' );
});