'a', 'y' => 'b']; $log = []; $res = Arrays::map( $arr, function ($v, $k, $arr) use (&$log) { $log[] = func_get_args(); return $v . $v; }, ); Assert::same(['x' => 'aa', 'y' => 'bb'], $res); Assert::same([['a', 'x', $arr], ['b', 'y', $arr]], $log); }); test('', function () { $arr = new ArrayIterator(['x' => 'a', 'y' => 'b']); $log = []; $res = Arrays::map( $arr, function ($v, $k, $arr) use (&$log) { $log[] = func_get_args(); return $v . $v; }, ); Assert::same(['x' => 'aa', 'y' => 'bb'], $res); Assert::same([['a', 'x', $arr], ['b', 'y', $arr]], $log); });