Example of how to get Order code in confirmation page

example_code.php

<?php
add_action('init', 'pmpro_example_code');

function pmpro_example_code() {
?>
	<script>
		document.addEventListener('DOMContentLoaded', function() {
			const code = pmpro.code;
			console.log(code);
		});
	</script>
<?php
}