Puli\Repository\AbstractJsonRepository::clear PHP Method

    public function clear()
    {
        if (null === $this->json) {
            $this->load();
        }
        // Subtract root which is not deleted
        $removed = count($this->getReferencesForRegex('/', '~.~')) - 1;
        $this->json = array();
        $this->flush();
        return $removed;
    }