Utils.php

<?php

class Utils
{
  private function __construct ()
  {
  }

  /**
   * @param array $array
   * @return array
   * Note : Recursively filters out empty values and arrays at any depth.
   */
  public static function recursiveArrayFilter (array $array): array
  {
    // First filter the array for non-empty elements
    $filtered = array_filter($array, function ($item) {
      if (is_array($item)) {
        // Recursively filter the sub-array
        $item = $this->recursiveArrayFilter($item);
        // Only retain non-empty arrays
        return !empty($item);
      } else {
        // Retain non-empty scalar values
        return !empty($item);
      }
    });

    return $filtered;
  }

  /**
   * Find matching keys between 2 lists.
   *
   * @param array|null $elements
   * @param array $keys
   * @return array
   */
  public static function findMatchingKeys (?array $elements, array $keys): array
  {
    $matching = [];

    if (!empty($elements)) {
      foreach ($elements as $element) {
        foreach ($keys as $key) {
          if (!empty($element) && array_key_exists($key, $element)) {
            $matching[] = $key;
          }
        }
      }
    }

    return $matching;
  }

  /**
   * @param $array
   * @return array
   * Note : simply return all values of a multi-dimensional array.
   */
  public static function getArrayValuesRecursive ($array)
  {
    $values = [];
    foreach ($array as $value) {
      if (is_array($value)) {
        // If value is an array, merge its values recursively
        $values = array_merge($values, self::getArrayValuesRecursive($value));
      } else {
        // If value is not an array, add it to the result
        $values[] = $value;