|string> */ public function rules(): array { return [ 'project_id' =>[ 'email' ], 'assets' => [ 'array', function ($attribute, $value, $fail) { $assetIds = Asset::query()->whereIn('id', $value)->pluck('id')->toArray(); if (count(array_diff($value, $assetIds)) > 0) { $fail('The selected asset is invalid.'); } } ], ]; } }