hook_schemadotorg_jsonld_schema_type_field_alter should get the schema_property value as parameter

Your request makes sense. Let me think about the implications before we make the change.

Below are hooks that could have $schema_type and $schema_property defined. Another approach is to add a $context that would allows $schema_mapping, $schema_type, and $schema_property.

hook_schemadotorg_jsonld_schema_type_field_alter(array &$data, \Drupal\Core\Field\FieldItemListInterface $items, \Drupal\Core\Render\BubbleableMetadata $bubbleable_metadata);

hook_schemadotorg_jsonld_schema_property_alter(mixed &$value, \Drupal\Core\Field\FieldItemInterface $item, \Drupal\Core\Render\BubbleableMetadata $bubbleable_metadata);

hook_schemadotorg_jsonld_schema_properties_alter(array &$values, \Drupal\Core\Field\FieldItemListInterface $items, \Drupal\Core\Render\BubbleableMetadata $bubbleable_metadata);

Passing the \Drupal\Core\Field\FieldItemInterface or \Drupal\Core\Field\FieldItemListInterface to the below hooks feels like the right thing to do, and we MUST pass the BubbleableMetadata, which allows JSON-LD to be cached.

hook_schemadotorg_jsonld_schema_type_field_alter(array &$data, \Drupal\Core\Field\FieldItemListInterface $items, \Drupal\Core\Render\BubbleableMetadata $bubbleable_metadata);

hook_schemadotorg_jsonld_schema_property_alter(mixed &$value, \Drupal\Core\Field\FieldItemInterface $item, \Drupal\Core\Render\BubbleableMetadata $bubbleable_metadata);

hook_schemadotorg_jsonld_schema_properties_alter(array &$values, \Drupal\Core\Field\FieldItemListInterface $items, \Drupal\Core\Render\BubbleableMetadata $bubbleable_metadata);

A maximum of 2 alterable arguments is supported. In case more arguments need to be passed and alterable, modules provide additional variables assigned by reference in the last $context argument:

@see https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Core%21Extension...

I experimented with adding $context, which contains the items, mapping, schema_type, and schema_property, and that started to feel ugly because users have started parsing through the $context. Moving $items to $context also breaks anyone's current implementation of these hooks.

The best compromise I can come up with is to provide a \Drupal\schemadotorg\Utility\SchemaDotOrgFieldHelper, which makes it easier to get the mapping, scheme type, and schema property.

Please review the attached proposed MR.

I think the SchemaDotOrgFieldHelper does improve things.