How can I change page title in node with some options? how can I change page title drupal 8 in node with some options?
I want change my title on "test" if node have field "field_section" is "dogs".
Just in this page I want showing in "field--node--title.html.twig" 'test'.

I tried 
function test_theme_preprocess_field(&amp;$variables, $hook) {
if($variables['field_name']=='title'){ 
   $variables['items']['changetitle']=true;
      // kint($variables);
   }
}

But I don't know how to search from preprocess field other paramters other fields like my field in node 'field_section'.

I want mix in preproccesing_field 'if field_section have value 'dogs' then showing page_title is 'test'.
You can fix all the things with 
RouteSubscriberBase
https://www.drupal.org/docs/8/api/routing-system/altering-existing-routes-and-adding-new-routes-based-on-dynamic-ones...

...

/** @var Route $entityUserEditForm */
$entityUserEditFormRoute = $collection-&gt;get('entity.user.edit_form');

// Change default user details entity form and title.
if ($entityUserEditFormRoute) {
  $entityUserEditFormRoute-&gt;setDefaults([
    '_entity_form' =&gt; 'user.complete_registration_form',
    '_title' =&gt; 'Complete Registration Form',
  ]);
}