Which function should I use to update a node through the comment form?

Question

I use this function to synchronize a comment field with the value from a field that exists in the node the comment belongs to.

function mymodule_comment_create(\Drupal\comment\CommentInterface $comment) {
  $node = $comment->getCommentedEntity();
  if ($node && $node instanceof \Drupal\node\NodeInterface) {
    if ($node->hasField('field_example')) {
      $comment->subject->value = $node->field_example->value;
    }
  }
}

How could I achieve the opposite? When a comment is submitted with the field field_rating, the field_average_rating field of the node should be updated.

How could I achieve that?

Answer 1

You could implement the same hook hook_comment_create() but just inverse the assignment you do on the comment as in your code, for example:

function mymodule_comment_create(\Drupal\comment\CommentInterface $comment) {
  $node = $comment->getCommentedEntity();
  if ($node && $node instanceof \Drupal\node\NodeInterface) {
    if ($node->hasField('node_field') && $comment->hasField('comment_field') && !empty($comment->comment_field->value)) {
      $node->node_field->value = $comment->comment_field->value;
    }
  }
}