tap() 辅助函数与 Tappable trait

function tap($value, $callback = null)
{
    if (is_null($callback)) {
        return new HigherOrderTapProxy($value);
    }

    $callback($value);

    return $value;
}

use App\Models\User;

$user = tap(User::query()->latest()->firstOrFail(), function (User $model) {
    $model->update(['last_seen_at' => now()]);
});

// 无论 update() 返回什么，最终返回的都是 $user

$updatedUser = tap($user)->update([
    'name' => $name,
    'email' => $email,
]);

// 返回原始 User 实例，而非 update() 的返回值

$result = tap($query->get(), function ($users) {
    logger()->debug('Fetched users', ['count' => $users->count()]);
});

$order = tap(Order::create($payload), function (Order $order) {
    event(new OrderCreated($order));
    logger()->info('Order created', ['id' => $order->id]);
});

$response = tap($service->handle($request), function ($response) {
    \Illuminate\Support\Facades\Cache::increment('service_handle_success_total');
});

trait Tappable
{
    public function tap($callback = null)
    {
        return tap($this, $callback);
    }
}

use Illuminate\Support\Traits\Tappable;

class ReportBuilder
{
    use Tappable;
}

$builder = new ReportBuilder();

$builder = $builder->tap(function (ReportBuilder $instance) {
    logger()->debug('builder initialized');
});

// 摘自 Illuminate\Routing\Router
$route = tap($this->routes->getByName($name))->bind($this->currentRequest);

return tap(static::toResponse($request, $response), function ($response) use ($request) {
    $this->events->dispatch(new ResponsePrepared($request, $response));
});