Laravel groupBy返回项的数组，而不是使用date作为键

$items = [
    ['name' => 'item1', 'date' => '2022-01-01'],
    ['name' => 'item2', 'date' => '2022-01-01'],
    ['name' => 'item3', 'date' => '2022-01-02'],
    ['name' => 'item4', 'date' => '2022-01-02'],
];

$groupedItems = collect($items)->groupBy('date')->map(function ($group) {
    return $group->pluck('name')->toArray();
})->toArray();

print_r($groupedItems);

Array
(
    [2022-01-01] => Array
        (
            [0] => item1
            [1] => item2
        )

    [2022-01-02] => Array
        (
            [0] => item3
            [1] => item4
        )

)