Custom plugin to send custom data from a text area after transaction success with Direct Stripe

ds-custom-data.php

<?php
/*
 * Plugin Name: Direct Stripe custom hooks
 * Author: Nicolas Figueira
 *
 */

//Add a textarea before the button
add_action( 'direct_stripe_before_button', function() {
  ?>
    <div class="sms-hook">
      <label><?php _e('The SMS content', 'textdomain'); ?></label>
      <textarea class="sms-content"></textarea>
  </div>
<?php
});

//GET transient and use sms data on transaction success
add_action( 'direct_stripe_before_success_redirection', function() {
  
  $sms = get_transient('sms_value');
  wp_mail( 'email_adress', 'subject', $sms);
  
  
});

//Add jQuery using wp_footer to get the data from the textarea 
add_action('wp_footer', function() {
  ?><script type="text/javascript">
      jQuery(".direct-stripe-button").on("click", function() {
          var sms = jQuery(".sms-content").val();
          var ajaxurl = <?php admin_url( 'admin-ajax.php' ); ?>
              jQuery.post(
                ajaxurl,
                {
                    'action': 'ds_set_sms',
                    'sms': sms
                }
            );
        });   
    </script>
  <?php 
});


//SET Transient
add_action( 'wp_ajax_ds_set_sms', 'ds_set_sms' );
add_action( 'wp_ajax_nopriv_ds_set_sms', 'ds_set_sms' );

function ds_set_sms() {
    $sms = isset($_POST['sms']) ? $_POST['sms'] : '';
		if( isset( $sms ) ) {
      set_transient("sms_value", $sms );
    }
}