laravel relation return array
/**
* Show all themes from a specific language
*
* @param Language $language
* @return \Illuminate\Database\Eloquent\Collection
*/
public function show(string $abbreviation)
{
return Theme::whereHas('language', function ($query) use ($abbreviation) {
$query->where('abbreviation', '=', $abbreviation);
})->get()->map(function ($theme) {
$theme['items'] = $theme->items()->get()->pluck('item')->all();
return $theme;
})->all();
}