Caramel-CRM-Backup/app/Http/Controllers/LineItemController.php

<?php

namespace App\Http\Controllers;

use App\Models\LineItem;
use App\Support\ApiDataTransformer;

class LineItemController extends Controller
{
    public function index($invoiceId)
    {
        $items = LineItem::with('unit')
            ->select('line_items.*')
            ->where('invoice_id', $invoiceId)
            ->orderBy('position', 'desc')
            ->get();

        return $items->map(function ($item) {
            $itemArray = $item->toArray();

            if ($item->unit) {
                $itemArray['unit_name'] = $item->unit->name;
                $itemArray['unit_symbol'] = $item->unit->symbol;
            }

            return ApiDataTransformer::snakeToCamel($itemArray);
        });
    }
}