class EntityReference

class EntityReference extends Fields {
    
    /**
     * {@inheritdoc}
     */
    protected function defineOptions() {
        $options = parent::defineOptions();
        $options['separator'] = [
            'default' => '-',
        ];
        return $options;
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildOptionsForm(&$form, FormStateInterface $form_state) {
        parent::buildOptionsForm($form, $form_state);
        // Expand the description of the 'Inline field' checkboxes.
        $form['inline']['#description'] .= '<br />' . $this->t("<strong>Note:</strong> In 'Entity Reference' displays, all fields will be displayed inline unless an explicit selection of inline fields is made here.");
    }
    
    /**
     * {@inheritdoc}
     */
    public function preRender($row) {
        // Force all fields to be inline by default.
        if (empty($this->options['inline'])) {
            $fields = $this->view
                ->getHandlers('field', $this->displayHandler->display['id']);
            $names = array_keys($fields);
            $this->options['inline'] = array_combine($names, $names);
        }
        return parent::preRender($row);
    }

}