Custom Stripe Elements description field

ee_stripe_description.php

<?php
//* Please do NOT include the opening php tag, except of course if you're starting with a blank file

add_filter(
    'FHEE__EEG_Stripe_Onsite__doDirectPaymentWithPaymentIntents__payment_intent_data',
    'stripe_elements_cf_order_desc', 10, 4
);
function stripe_elements_cf_order_desc(
    $stripe_data,
    $payment,
    $transaction,
    $billing_info
) {
  if ($transaction instanceof EEI_Transaction) {
    $primary_registrant = $transaction->primary_registration();
    if ($primary_registrant instanceof EE_Registration) {
      $event = $primary_registrant->event_obj();
      if ($event instanceof EEI_Event) {
        $desc = $event->name();
        $desc .= ' | cost code: ' . get_post_meta($event->id(), 'cost_code', true);
        $stripe_data['description'] = $desc;
      }
    }
  }
  return $stripe_data;
}