createSettingsFromCKEditor4 example

$source_editing_additions = HTMLRestrictions::emptySet();
    // Compute the appropriate settings based on the CKEditor 4 configuration     // if it exists.     $old_editor = $editor->id() ? Editor::load($editor->id()) : NULL;
    $old_editor_restrictions = $old_editor ? HTMLRestrictions::fromTextFormat($old_editor->getFilterFormat()) : HTMLRestrictions::emptySet();
    // @todo Remove in https://www.drupal.org/project/drupal/issues/3245351     if ($old_editor) {
      $editor->setImageUploadSettings($old_editor->getImageUploadSettings());
    }
    if ($old_editor && $old_editor->getEditor() === 'ckeditor') {
      [$upgraded_settings, $messages] = $this->createSettingsFromCKEditor4($old_editor->getSettings(), HTMLRestrictions::fromTextFormat($old_editor->getFilterFormat()));
      $editor->setSettings($upgraded_settings);
      // *Before* determining which elements are still needed for this text       // format, ensure that all already enabled plugins that are configurable       // have valid settings.       // For all already enabled plugins, find the ones that are configurable,       // and add their default settings. For enabled plugins with element       // subsets, compute the appropriate settings to achieve the subset that       // matches the original text format restrictions.       $this->addDefaultSettingsForEnabledConfigurablePlugins($editor);
      $this->computeSubsetSettingForEnabledPluginsWithSubsets($editor, $text_format);
    }