public function jsonSerialize()
    {
        return array_filter(
            [
                'enable' => $this->getEnable(),
                'utm_source' => $this->getCampaignSource(),
                'utm_medium' => $this->getCampaignMedium(),
                'utm_term' => $this->getCampaignTerm(),
                'utm_content' => $this->getCampaignContent(),
                'utm_campaign' => $this->getCampaignName()
            ],
            function ($value) {
                return $value !== null;
            }
        ) ?: null;
    }