JSFiddle - React, Tailwind, and code Playground

HTML

<textarea name="textarea" cols="20" rows="5" id="test"
 onKeyUp="call(this.value);"></textarea>

<textarea style="display:block" cols="20" rows="5" id="result" disabled></textarea>

JavaScript

function call(val) {
    document.getElementById('result').value += val.charAt(val.length - 1);


    document.getElementById('result').value = document.getElementById('result').value.substr(0, val.length);


    document.getElementById('test').value = document.getElementById('test').value.replace(/[^\^]/g, ' ');

}