FieldInstanceDefaults.php

<?php

namespace Drupal\field\Plugin\migrate\process\d6;

use Drupal\migrate\MigrateExecutableInterface;
use Drupal\migrate\ProcessPluginBase;
use Drupal\migrate\Row;
// cspell:ignore imagefield

/**
 * @MigrateProcessPlugin(
 *   id = "d6_field_instance_defaults"
 * )
 */
class FieldInstanceDefaults extends ProcessPluginBase {
    
    /**
     * {@inheritdoc}
     *
     * Set the field instance defaults.
     */
    public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
        [
            $widget_type,
            $widget_settings,
        ] = $value;
        $default = [];
        switch ($widget_type) {
            case 'text_textfield':
            case 'number':
            case 'phone_textfield':
                if (!empty($widget_settings['default_value'][0]['value'])) {
                    $default['value'] = $widget_settings['default_value'][0]['value'];
                }
                break;
            case 'imagefield_widget':
                // @todo, load the image and populate the defaults.
                // $default['default_image'] = $widget_settings['default_image'];
                break;
            case 'date_select':
                if (!empty($widget_settings['default_value'])) {
                    $default['default_date_type'] = 'relative';
                    $default['default_date'] = $widget_settings['default_value'];
                }
                break;
            case 'email_textfield':
                if (!empty($widget_settings['default_value'][0]['email'])) {
                    $default['value'] = $widget_settings['default_value'][0]['email'];
                }
                break;
            case 'link':
                if (!empty($widget_settings['default_value'][0]['url'])) {
                    $default['title'] = $widget_settings['default_value'][0]['title'];
                    $default['uri'] = $widget_settings['default_value'][0]['url'];
                    $default['options'] = [
                        'attributes' => [],
                    ];
                }
                break;
        }
        if (!empty($default)) {
            $default = [
                $default,
            ];
        }
        return $default;
    }

}