How to set a default value on an address field during Commerce Checkout?

Question

I'm having a tough time setting a default value on an Address field during Commerce checkout.

The Address (profile) is set to use the Address First & Last name fields and I'm trying to set their default values (since the user already entered their name on the registration page prior).

I've tried _form_alter, _preprocess_input, and _field_widget_form_alter - but I am not able to get any of these to work - I suspect because the address widget is displayed on a Commerce checkout screen may be making this more difficult.

Any advise on how to set these default values?

Drupal 10 / Commerce

Answer 1

function MODULE_form_commerce_checkout_flow_multistep_default_alter(&$form, \Drupal\Core\Form\FormStateInterface $form_state, $form_id) {

  if ($form['#step_id'] == 'order_information') {

    // Set first & last name from user account
    $form['payment_information']['add_payment_method']['billing_information']['address']['widget'][0]['address']['#pre_render'][] =  [MyPreRenders::class, 'recurringCodePrerender'];
}

MODULE/src/MyPreRenders

namespace Drupal\MODULE;

use Drupal\Core\Security\TrustedCallbackInterface;
use Drupal\Core\Security\Attribute\TrustedCallback;

class MyPreRenders {
  #[TrustedCallback]
  public static function recurringCodePrerender($form) {

    $user = \Drupal\user\Entity\User::load(\Drupal::currentUser()->id());

    $form['given_name']['#value'] = $user->get('field_first_name')->value;
    $form['family_name']['#value'] = $user->get('field_last_name')->value;

    return $form;
  }
}