src/Flintstone.php
public function getKeys(): array
    {
        $keys = [];
        $file = $this->getDatabase()->readFromFile();

        foreach ($file as $line) {
            /** @var Line $line */
            $keys[] = $line->getKey();
        }

        return $keys;
    }
public function getKeys(): array
    {
        $keys = [];
        $file = $this->getDatabase()->readFromFile();

        foreach ($file as $line) {
            /** @var Line $line */
            $keys[] = $line->getKey();
        }

        return $keys;
    }
Get all keys from the database.

@return array