This is optimization tags for ManyToMany relationship with Post model for attaching not existing tags.

tags.php

public function store(Post $post)
{
    $tags = [];

    foreach ((array) request('tags') as $tag_name) {
        $tags[] = Tag::firstOrNew(['name' => $tag_name]);
    }

    // a dla fanow adama wathana o jedna linijke mniej:
    // 
    // $tags = collect((array) request('tags'))->map(function ($tag_name) {
    //     return Tag::firstOrNew(['name' => $tag_name]);
    // });

    $post->tags()->saveMany($tags);
}