JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" id="example">
<button id="start">Start auto typing</button>

JavaScript

var _keystroke_interval = 500;
var autoText = ['f','o','o','b','a','r'];
var characterIndex = 0;
var autoType = '';
$(function(){

    $("#start").on('click',function(){
        autoType = setInterval(function(){
            $("#example").val( $("#example").val() + autoText[characterIndex] );
            characterIndex++;
            if (characterIndex >= autoText.length){
                clearInterval(autoType);
            }
        },_keystroke_interval);  
    });

});