project/app/Http/Controllers/Api/InvoiceitemController.php

<?php

namespace App\Http\Controllers\Api;

use App\Http\Controllers\Controller;
use App\Models\Invoice;
use App\Models\Invoiceitem;
use Illuminate\Http\JsonResponse;
use Illuminate\Http\Request;

class InvoiceitemController extends Controller
{
    /**
     * Display a listing of the resource.
     */
    public function index(Invoice $invoice): JsonResponse
    {
        return response()->json($invoice->items);
    }

    /**
     * Store a newly created resource in storage.
     */
    public function store(Request $request, Invoice $invoice): JsonResponse
    {
        $itemData = $request->validate([
            'amount' => 'required|numeric|min:0',
            'discount' => 'numeric|nullable',
            'tax' => 'required|numeric|min:0',
            'price' => 'required|numeric|min:0',
            'total' => 'required|numeric|min:0',
            'name' => 'required|string',
            'description' => 'nullable|string',
            'article_number' => 'nullable|string',
            'sort' => 'required|numeric|min:0',
        ]);

        $item = $invoice->items()->create($itemData);
        return response()->json($item);
    }

    /**
     * Display the specified resource.
     */
    public function show(Invoiceitem $invoiceitem)
    {
        //
    }

    /**
     * Update the specified resource in storage.
     */
    public function update(Request $request, Invoiceitem $invoiceitem)
    {
        //
    }

    /**
     * Remove the specified resource from storage.
     */
    public function destroy(Invoiceitem $invoiceitem)
    {
        //
    }
}