JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
    <textarea id="input">Bentley's gonna sort you out!</textarea>
</div>

CSS

div#container textarea {
    overflow-y: hidden; /* prevents scroll bar flash */
    padding-top: 1.1em; /* prevents text jump on Enter keypress */
}

JavaScript

// auto adjust the height of
$('#input').on( 'keydown', 'textarea', function (e){
    $(this).css('height', 'auto' );
    $(this).height( this.scrollHeight );
});
$('#input').find( 'textarea' ).keydown();