Error message

• Warning: Undefined array key -1 in fas_family_change_preprocess_node__book() (line 156 of themes/custom/fas_family_change/fas_family_change.theme).

  fas_family_change_preprocess_node__book()
  call_user_func_array() (Line: 308)
  Drupal\Core\Theme\ThemeManager->render() (Line: 497)
  Drupal\Core\Render\Renderer->doRender() (Line: 227)
  Drupal\Core\Render\Renderer->render() (Line: 242)
  Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}() (Line: 627)
  Drupal\Core\Render\Renderer->executeInRenderContext() (Line: 235)
  Drupal\Core\Render\MainContent\HtmlRenderer->prepare() (Line: 131)
  Drupal\Core\Render\MainContent\HtmlRenderer->renderResponse() (Line: 90)
  Drupal\Core\EventSubscriber\MainContentViewSubscriber->onViewRenderArray() (Line: 246)
  Symfony\Component\EventDispatcher\EventDispatcher::Symfony\Component\EventDispatcher\{closure}() (Line: 206)
  Symfony\Component\EventDispatcher\EventDispatcher->callListeners() (Line: 56)
  Symfony\Component\EventDispatcher\EventDispatcher->dispatch() (Line: 188)
  Symfony\Component\HttpKernel\HttpKernel->handleRaw() (Line: 76)
  Symfony\Component\HttpKernel\HttpKernel->handle() (Line: 43)
  Drupal\redirect_after_login\RedirectMiddleware->handle() (Line: 53)
  Drupal\Core\StackMiddleware\Session->handle() (Line: 48)
  Drupal\Core\StackMiddleware\KernelPreHandle->handle() (Line: 28)
  Drupal\Core\StackMiddleware\ContentLength->handle() (Line: 201)
  Drupal\page_cache\StackMiddleware\PageCache->fetch() (Line: 138)
  Drupal\page_cache\StackMiddleware\PageCache->lookup() (Line: 87)
  Drupal\page_cache\StackMiddleware\PageCache->handle() (Line: 48)
  Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle() (Line: 51)
  Drupal\Core\StackMiddleware\NegotiationMiddleware->handle() (Line: 53)
  Drupal\Core\StackMiddleware\AjaxPageState->handle() (Line: 51)
  Drupal\Core\StackMiddleware\StackedHttpKernel->handle() (Line: 715)
  Drupal\Core\DrupalKernel->handle() (Line: 19)
  

• Warning: Trying to access array offset on null in fas_family_change_preprocess_node__book() (line 156 of themes/custom/fas_family_change/fas_family_change.theme).

  fas_family_change_preprocess_node__book()
  call_user_func_array() (Line: 308)
  Drupal\Core\Theme\ThemeManager->render() (Line: 497)
  Drupal\Core\Render\Renderer->doRender() (Line: 227)
  Drupal\Core\Render\Renderer->render() (Line: 242)
  Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}() (Line: 627)
  Drupal\Core\Render\Renderer->executeInRenderContext() (Line: 235)
  Drupal\Core\Render\MainContent\HtmlRenderer->prepare() (Line: 131)
  Drupal\Core\Render\MainContent\HtmlRenderer->renderResponse() (Line: 90)
  Drupal\Core\EventSubscriber\MainContentViewSubscriber->onViewRenderArray() (Line: 246)
  Symfony\Component\EventDispatcher\EventDispatcher::Symfony\Component\EventDispatcher\{closure}() (Line: 206)
  Symfony\Component\EventDispatcher\EventDispatcher->callListeners() (Line: 56)
  Symfony\Component\EventDispatcher\EventDispatcher->dispatch() (Line: 188)
  Symfony\Component\HttpKernel\HttpKernel->handleRaw() (Line: 76)
  Symfony\Component\HttpKernel\HttpKernel->handle() (Line: 43)
  Drupal\redirect_after_login\RedirectMiddleware->handle() (Line: 53)
  Drupal\Core\StackMiddleware\Session->handle() (Line: 48)
  Drupal\Core\StackMiddleware\KernelPreHandle->handle() (Line: 28)
  Drupal\Core\StackMiddleware\ContentLength->handle() (Line: 201)
  Drupal\page_cache\StackMiddleware\PageCache->fetch() (Line: 138)
  Drupal\page_cache\StackMiddleware\PageCache->lookup() (Line: 87)
  Drupal\page_cache\StackMiddleware\PageCache->handle() (Line: 48)
  Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle() (Line: 51)
  Drupal\Core\StackMiddleware\NegotiationMiddleware->handle() (Line: 53)
  Drupal\Core\StackMiddleware\AjaxPageState->handle() (Line: 51)
  Drupal\Core\StackMiddleware\StackedHttpKernel->handle() (Line: 715)
  Drupal\Core\DrupalKernel->handle() (Line: 19)