JSFiddle - React, Tailwind, and code Playground

HTML

<textarea id='a' style="width:100%;height:300px;"></textarea>

JavaScript

var textArea = document.getElementById('a');

for (var i = 0; i < 50; i++) {
    setTimeout(
        (function(i) {
            return function() {
                textArea.value += 'Mensagem ' + i + '\n';
                textArea.scrollTop = textArea.scrollHeight;
            }
        })(i), 100 * i);
}