Usage

Add the HasSearchableRelations trait to any Eloquent model whose changes should trigger re-indexing of related models. Then override searchableRelations() to return the relationship names to watch.

use Foxws\ScoutRelations\Concerns\HasSearchableRelations;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\HasMany;

class Author extends Model
{
    use HasSearchableRelations;

    /**
     * Relationships whose models should be re-indexed when this model changes.
     *
     * @return array<int, string>
     */
    public function searchableRelations(): array
    {
        return ['posts'];
    }

    public function posts(): HasMany
    {
        return $this->hasMany(Post::class);
    }
}

The related Post model must use Laravel Scout's Searchable trait:

use Illuminate\Database\Eloquent\Model;
use Laravel\Scout\Searchable;

class Post extends Model
{
    use Searchable;

    public function toSearchableArray(): array
    {
        return [
            'id'          => $this->id,
            'title'       => $this->title,
            'author_name' => $this->author->name, // kept fresh on every re-index
        ];
    }
}

Now whenever an Author is saved with changes or deleted, all of its Post records are automatically re-indexed.

How it works

The trait hooks into Eloquent's saved and deleted model events:

• saved — re-indexes relations only when wasChanged() is true, avoiding unnecessary indexing on no-op saves.
• deleted — re-indexes relations unconditionally so the search index reflects the parent's removal.

Re-indexing is performed in chunks via chunkById. If the related model defines makeAllSearchableUsing(), it is applied to the chunk query, preventing N+1 queries.

A per-class re-entry guard prevents infinite cascades when mutual relationships exist.