How to add the paragraph parent field in the theme suggestions alter

Question

I've been spending a couple of hours from debugging the paragraph properties using kint and var_dumper however, the page is freezing and I'm unable to see what are the properties and methods available. Has anyone tried to add a hook theme suggestion to paragraph based on its parent field name?

I have added a paragraph type as well as added the fields, then I created a node and paragraph reference.

Here's a sample code:-

function THEMENAME_theme_suggestions_paragraph_alter(&$suggestions, $variables) {
    $paragraph = $variables['elements']['#paragraph'];
    $parent = $paragraph->getParentEntity();

    $suggestions[] = 'paragraph__' . $parent->bundle() . '__' .  $paragraph->bundle();

    // get the parent field of the current paragraph
    // assuming that the parent field name is field_test_paragraph
    $parent_field_name = 'field_test_paragraph';

    // field_test_paragraph should be added to theme suggestions
    $suggestions[] = 'paragraph__' . $parent->bundle() . __ . $parent_field_name . '__' .  $paragraph->bundle();
}

Expected output:

paragraph--nodetype--field-test-paragraph--paragraph-type-name.html.twig

Answer 1

You can get the parent field name directly from the paragraph:

Replace

// get the parent field of the current paragraph
// assuming that the parent field name is field_test_paragraph
$parent_field_name = 'field_test_paragraph';

with

$parent_field_name = $paragraph->parent_field_name->value;

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As a side note, this is an entity base field like parent_id and parent_type you load the parent entity with in getParentEntity().