How to show new line in the alert popup from json_encode?

I am showing a popup window using ajax after calling my php file whenever I am able to write successfully in a file.

I am showing popup using below code where I use alert.

<script src="https://code.jquery.com/jquery-3.5.1.min.js"></script>
<script>
$(function() {
    $('form').submit(function(e) {
        e.preventDefault();
        $.post({
            url: 'savefile.php',
            data: $(this).serialize(),
        }).done(response => {
            console.log(response);
            response = JSON.parse(response);
            if(response.message) {
                alert(response.message);
            }
        });
    });
});
</script>

The json I am returning is this:

echo json_encode([
    'success' => true,
    'message' => $ret . ' bytes saved to file. \n All data saved.',
]);

I wanted to show on popup as shown below where All data saved. goes in new line instead of getting shown in the same line. But when I try above code it is just escaping it instead of showing in new line. Is there any clean way to do this?

10 bytes saved to file.
All data saved.