Laravel Sluggable Trait Version 2

Sluggable.php

<?php

/**
* PHP v7+
* Remember for this to work, in your controller you need to do:
* $model->slug = request('title')
* columns name are: title and slug
*/

namespace App\Traits;

trait Sluggable
{
	/**
	 * Get the Slug instead of id
	 *
	 * @return string
	 */
	public function getRouteKeyName()
	{
		return 'slug';
	}

	/**
	 * Slug Mutator
	 * 
	 * @param $value
	 */
	public function setSlugAttribute($value)
	{
		if (static::whereSlug($slug = make_slug($value))->exists()) {
			$slug = $this->incrementSlug($slug);
		}
		$this->attributes['slug'] = $slug;
	}

	/**
	 * Increment Slug
	 * 
	 * @param $slug
	 * @return mixed|string
	 */
	public function incrementSlug($slug)
	{
		$max = static::where('title', $this->title)->latest('id')->value('slug');

		if (is_numeric($max[-1])) {
			return preg_replace_callback('/(\d+)$/iu', function ($matches) {
				return $matches[1] + 1;
			}, $max);
		}

		return "{$slug}-2";
	}
}