class Editor

class Editor extends PluginBase implements InPlaceEditorInterface {
    
    /**
     * {@inheritdoc}
     */
    public function isCompatible(FieldItemListInterface $items) {
        $field_definition = $items->getFieldDefinition();
        // This editor is incompatible with multivalued fields.
        if ($field_definition->getFieldStorageDefinition()
            ->getCardinality() != 1) {
            return FALSE;
        }
        elseif ($editor = editor_load($items[0]->format)) {
            $definition = \Drupal::service('plugin.manager.editor')->getDefinition($editor->getEditor());
            if ($definition['supports_inline_editing'] === TRUE) {
                return TRUE;
            }
        }
        return FALSE;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getMetadata(FieldItemListInterface $items) {
        $format_id = $items[0]->format;
        $metadata['format'] = $format_id;
        $metadata['formatHasTransformations'] = $this->textFormatHasTransformationFilters($format_id);
        return $metadata;
    }
    
    /**
     * Returns whether the text format has transformation filters.
     *
     * @param int $format_id
     *   A text format ID.
     *
     * @return bool
     */
    protected function textFormatHasTransformationFilters($format_id) {
        $format = FilterFormat::load($format_id);
        return (bool) count(array_intersect([
            FilterInterface::TYPE_TRANSFORM_REVERSIBLE,
            FilterInterface::TYPE_TRANSFORM_IRREVERSIBLE,
        ], $format->getFiltertypes()));
    }
    
    /**
     * {@inheritdoc}
     */
    public function getAttachments() {
        $user = \Drupal::currentUser();
        $user_format_ids = array_keys(filter_formats($user));
        $manager = \Drupal::service('plugin.manager.editor');
        $definitions = $manager->getDefinitions();
        // Filter the current user's formats to those that support inline editing.
        $formats = [];
        foreach ($user_format_ids as $format_id) {
            if ($editor = editor_load($format_id)) {
                $editor_id = $editor->getEditor();
                if (isset($definitions[$editor_id]['supports_inline_editing']) && $definitions[$editor_id]['supports_inline_editing'] === TRUE) {
                    $formats[] = $format_id;
                }
            }
        }
        // Get the attachments for all text editors that the user might use.
        $attachments = $manager->getAttachments($formats);
        // Also include quickedit.module's formatted text editor.
        $attachments['library'][] = 'quickedit/quickedit.inPlaceEditor.formattedText';
        return $attachments;
    }

}