JSFiddle - React, Tailwind, and code Playground
HTML
<textarea id="field"></textarea>
<div id="charNum">10</div>
JavaScript
$("#field").keyup(function(){
el = $(this);
if(el.val().length >= 11){
el.val( el.val().substr(0, 10) );
} else {
$("#charNum").text(10-el.val().length);
}
});