FirstOrLast.php

<?php

declare (strict_types=1);
namespace Drupal\Core\Hook\OrderOperation;


/**
 * Moves one listener to the start or end of the list.
 *
 * @internal
 */
class FirstOrLast extends OrderOperation {
    
    /**
     * Constructor.
     *
     * @param string $identifier
     *   Identifier of the implementation to move to a new position. The format
     *   is the class followed by "::" then the method name. For example,
     *   "Drupal\my_module\Hook\MyModuleHooks::methodName".
     * @param bool $isLast
     *   TRUE to move to the end, FALSE to move to the start.
     */
    public function __construct(string $identifier, bool $isLast) {
    }
    
    /**
     * {@inheritdoc}
     */
    public function apply(array &$identifiers, array $module_finder) : void {
        $index = array_search($this->identifier, $identifiers);
        if ($index === FALSE) {
            // The element does not exist.
            return;
        }
        unset($identifiers[$index]);
        if ($this->isLast) {
            $identifiers[] = $this->identifier;
        }
        else {
            $identifiers = [
                $this->identifier,
                $identifiers,
            ];
        }
        $identifiers = array_values($identifiers);
    }

}