PHP 7.2 Anonymous Class vs Array - Memory Test

php-7.2-anon-class-vs-array-mem.md

PHP 7.2 real app usage:

public function jsonSerialize()
    {
        $m1 = memory_get_usage();
        $json_class = new class implements SpecExportInterface {
            public $id;
            public $status;
            public $code;
            public $title;
            public $source;
            public $links;
        };
        $m2 = memory_get_usage();
        $json_class->id     = $this->id;
        $json_class->status = $this->status;
        $json_class->code   = $this->code;
        $json_class->title  = $this->title;
        $json_class->source = $this->source;
        $json_class->links  = $this->links;
        $m3 = memory_get_usage();
        $a1 = [];
        $m4 = memory_get_usage();
        $a1['id']     = $this->id;
        $a1['status'] = $this->id;
        $a1['code']   = $this->id;
        $a1['title']  = $this->id;
        $a1['source'] = $this->id;
        $a1['links']  = $this->id;
        $a1['id']     = $this->id;
        $m5 = memory_get_usage();

        echo 'class create:' . ($m2-$m1) . '</br>'
            .'class assign:'  . ($m3-$m2) . '</br>'
            .'array create:' . ($m4-$m3) . '</br>'
            .'array assign:'  . ($m5-$m4) . '</br>'
            ;die;

        return $json_class;
    }

Results:

class create: 168 bytes
class assign: 0 bytes
array create: 0 bytes
array assign: 376 bytes