JSFiddle - React, Tailwind, and code Playground

HTML

<textarea></textarea>
<div id="text"></div>

CSS

#text {
  position: absolute;
  height: auto;
  width: auto;
}

JavaScript

$('textarea').on('keyup', function() {
    var last = $(this).val().split('\n').pop();
    var width = $('#text').text(last).width(); 
    if ( width >  $('textarea').width() ) {
      alert('wrap')
    }
});