FluidTYPO3\Vhs\ViewHelpers\Iterator\ExtractViewHelper::extractByKey PHP Метод

    public function extractByKey($iterator, $key)
    {
        if (false === is_array($iterator) && false === $iterator instanceof \Traversable) {
            throw new \Exception('Traversable object or array expected but received ' . gettype($iterator), 1361532490);
        }
        $result = ObjectAccess::getPropertyPath($iterator, $key);
        return $result;
    }

 /**
  * @test
  * @dataProvider simpleStructures
  */
 public function extractByKeyExtractsKeyByPath($structure, $key, $expected)
 {
     $this->assertSame($expected, $this->fixture->extractByKey($structure, $key));
 }