Online PHP editor | vld for 0vT33

<?php class A implements \JsonSerializable { public $prop; public function jsonSerialize() { $obj = new stdClass; if ($this->prop) { $obj->prop = $this->prop; } return $obj; } } class B implements \JsonSerializable { public $a; public function jsonSerialize() { $obj = new stdClass; if ($this->a) { $obj->a = $this->a; } return $obj; } } $a = new A; $b = new B; $b->a = $a; var_dump(json_encode($b));