Get an array of duplicate field values.

Parameters

array $item_values: The item values.

Return value

array Item values only for deltas that duplicate an earlier delta.

1 call to UniqueFieldValueValidator::extractDuplicates()

UniqueFieldValueValidator::validate in core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/UniqueFieldValueValidator.php

File

core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/UniqueFieldValueValidator.php, line 155

Class

UniqueFieldValueValidator

Validates that a field is unique for the given entity type.

Namespace

Drupal\Core\Validation\Plugin\Validation\Constraint

Code

private function extractDuplicates(array $item_values) : array {
  $value_frequency = array_count_values($item_values);
  // Filter out item values which are not duplicates while preserving deltas
  $duplicate_values = array_intersect($item_values, array_keys(array_filter($value_frequency, function ($value) {
    return $value > 1;
  })));
  // Exclude the first delta of each duplicate value.
  $first_deltas = array_unique($duplicate_values);
  return array_diff_key($duplicate_values, $first_deltas);
}

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