3v4l.org

run code in 300+ PHP versions simultaneously
<?php class Foo implements JsonSerializable { private $thing; public function __construct($thing) { $this->thing = $thing; } public function jsonSerialize() { return [ 'thing' => $this->thing, ]; } } $foo = new Foo('Foo Bar'); echo json_encode(['the_foo' => $foo]);
Output for 8.1rc2
Deprecated: Return type of Foo::jsonSerialize() should either be compatible with JsonSerializable::jsonSerialize(): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /in/c9UeF on line 12 {"the_foo":{"thing":"Foo Bar"}}
Output for 8.1rc1
Deprecated: Return type of Foo::jsonSerialize() should either be compatible with JsonSerializable::jsonSerialize(): mixed, or the #[ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /in/c9UeF on line 12 {"the_foo":{"thing":"Foo Bar"}}
Output for 7.2.0 - 7.2.33, 7.3.0 - 7.3.30, 7.4.0 - 7.4.23, 8.0.0 - 8.0.11
{"the_foo":{"thing":"Foo Bar"}}

preferences:
78.66 ms | 462 KiB | 5 Q