class ShortcutSetForm

class ShortcutSetForm extends BundleEntityFormBase {
    
    /**
     * {@inheritdoc}
     */
    public function form(array $form, FormStateInterface $form_state) {
        $form = parent::form($form, $form_state);
        $entity = $this->entity;
        $form['label'] = [
            '#type' => 'textfield',
            '#title' => $this->t('Set name'),
            '#description' => $this->t('The new set is created by copying links from your default shortcut set.'),
            '#required' => TRUE,
            '#default_value' => $entity->label(),
        ];
        $form['id'] = [
            '#type' => 'machine_name',
            '#machine_name' => [
                'exists' => '\\Drupal\\shortcut\\Entity\\ShortcutSet::load',
                'source' => [
                    'label',
                ],
                'replace_pattern' => '[^a-z0-9-]+',
                'replace' => '-',
            ],
            '#default_value' => $entity->id(),
            // This id could be used for menu name.
'#maxlength' => 23,
        ];
        $form['actions']['submit']['#value'] = $this->t('Create new set');
        return $this->protectBundleIdElement($form);
    }
    
    /**
     * {@inheritdoc}
     */
    public function save(array $form, FormStateInterface $form_state) {
        $entity = $this->entity;
        $is_new = !$entity->getOriginalId();
        $entity->save();
        if ($is_new) {
            $this->messenger()
                ->addStatus($this->t('The %set_name shortcut set has been created. You can edit it from this page.', [
                '%set_name' => $entity->label(),
            ]));
        }
        else {
            $this->messenger()
                ->addStatus($this->t('Updated set name to %set-name.', [
                '%set-name' => $entity->label(),
            ]));
        }
        $form_state->setRedirectUrl($this->entity
            ->toUrl('customize-form'));
    }

}