Laravel - set a field into a slug on record insert

Model.php

<?php
    /**
     * Set name field to slug on insert
     *
     * @param $name
     */
    public function setNameAttribute($name)
    {
        $this->attributes['name'] = $name;

        if (!$this->exists) {
            $this->setUniqueSlug($name, '');
        }
    }

    /**
     * Recursive routine to set unique slug
     *
     * @param $name
     * @param $extra
     */
    protected function setUniqueSlug($name, $extra)
    {
        $slug = str_slug($name.'-'.$extra);

        if (static::whereSlug($slug)->exists()) {
            $this->setUniqueSlug($name, $extra + 1);
            return;
        }

        $this->attributes['slug'] = $slug;
    }