JSFiddle - React, Tailwind, and code Playground

HTML

<!doctype html>
<html>
<body>
<script>
function heidiDecode(hex) {
    var str = '';
    var shift = parseInt(hex.substr(-1));
    hex = hex.substr(0, hex.length - 1);
    for (var i = 0; i < hex.length; i += 2) 
        str += String.fromCharCode(parseInt(hex.substr(i, 2), 16) - shift); 
    return str; 
} 
document.write(heidiDecode('46554F4F317472643')); </script>
</body>
</html>