Laravel 8 whereInstanceOf() {#collection-method}

whereInstanceOf 方法根据给定的类来过滤集合：

use App\Models\User;
use App\Models\Post;

$collection = collect([
    new User,
    new User,
    new Post,
]);

$filtered = $collection->whereInstanceOf(User::class);

$filtered->all();

// [App\Models\User, App\Models\User]