laravel request ajax always return false - ajax

Question

i have problem working with laravel request->ajax() its always return false. so the if statement is not working on what function is to be called. Im using datatables to render the table.
this code i have is not working properply
ContactController.php
public function index()
{
$type = request()->get('type');
$types = ['supplier', 'customer'];
if (empty($type) || !in_array($type, $types)) {
return redirect()->back();
}
if (request()->ajax()) {
if ($type == 'supplier') {
return $this->indexSupplier();
} elseif ($type == 'customer') {
return $this->indexCustomer();
} else {
die("Not Found");
}
}
$reward_enabled = (request()->session()->get('business.enable_rp') == 1 && in_array($type, ['customer'])) ? true : false;
return view('contact.index')
->with(compact('type', 'reward_enabled'));
}
private function indexSupplier()
{
if (!auth()->user()->can('supplier.view') && !auth()->user()->can('supplier.view_own')) {
abort(403, 'Unauthorized action.');
}
$business_id = request()->session()->get('user.business_id');
$contact = $this->contactUtil->getContactQuery($business_id, 'supplier');
if (request()->has('has_purchase_due')) {
$contact->havingRaw('(total_purchase - purchase_paid) > 0');
}
if (request()->has('has_purchase_return')) {
$contact->havingRaw('total_purchase_return > 0');
}
if (request()->has('has_advance_balance')) {
$contact->where('balance', '>', 0);
}
if (request()->has('has_opening_balance')) {
$contact->havingRaw('opening_balance > 0');
}
return Datatables::of($contact)
...
}
private function indexCustomer()
{
if (!auth()->user()->can('customer.view') && !auth()->user()->can('customer.view_own')) {
abort(403, 'Unauthorized action.');
}
$business_id = request()->session()->get('user.business_id');
$is_admin = $this->contactUtil->is_admin(auth()->user());
$query = $this->contactUtil->getContactQuery($business_id, 'customer');
return Datatables::of($query)
...
}
this is the sidebarblade that links to the controller.
if (auth()->user()->can('supplier.view') || auth()->user()->can('supplier.view_own')) {
$sub->url(action('ContactController#index', ['type' => 'supplier']),__('report.supplier'),
['icon' => 'fa fas fa-star', 'active' => request()->input('type') == 'upplier']);
}
if (auth()->user()->can('customer.view') || auth()->user()->can('customer.view_own')) {
$sub->url(action('ContactController#index', ['type' => 'customer']),__('report.customer'),
['icon' => 'fa fas fa-star', 'active' => request()->input('type') == 'customer']);
$sub->url(action('CustomerGroupController#index'),__('lang_v1.customer_groups'),
['icon' => 'fa fas fa-users', 'active' => request()->segment(1) == 'customer-group']);
}