src/Database/Traits/HasPermalink.php
public function getSlugKeyName()
    {
        if (property_exists($this, 'slugKeyName')) {
            return $this->slugKeyName;
        }

        $config = $this->permalinkable();
        $name = reset($config);
        $key = key($config);

        // check for short configuration
        if ($key === 0) {
            return $name;
        }

        return $key;
    }
public function getSlugKeyName()
    {
        if (property_exists($this, 'slugKeyName')) {
            return $this->slugKeyName;
        }

        $config = $this->permalinkable();
        $name = reset($config);
        $key = key($config);

        // check for short configuration
        if ($key === 0) {
            return $name;
        }

        return $key;
    }
Primary slug column of this model.
@return string