rfc6455/src/Messaging/CloseFrameChecker.php

<?php
namespace mfmdevsystem\RFC6455\Messaging;

class CloseFrameChecker {
    private array $validCloseCodes = [
        Frame::CLOSE_NORMAL,
        Frame::CLOSE_GOING_AWAY,
        Frame::CLOSE_PROTOCOL,
        Frame::CLOSE_BAD_DATA,
        Frame::CLOSE_BAD_PAYLOAD,
        Frame::CLOSE_POLICY,
        Frame::CLOSE_TOO_BIG,
        Frame::CLOSE_MAND_EXT,
        Frame::CLOSE_SRV_ERR,
    ];

    public function __invoke(int $val): bool {
        return ($val >= 3000 && $val <= 4999) || in_array($val, $this->validCloseCodes);
    }
}