@foreach($iscategories as $category)
    <option value="{{ $category->id }}">{{ ($prefix ?? '') }}{{ $category->name }}</option>
    @if($category->children && $category->children->count())
        @include('isms.category-options', [
            'categories' => $category->children, 
            'prefix' => ($prefix ?? '') . '--'
        ])
    @endif
@endforeach