Filter record using from date and to date

In my case, I have to filter records by using from-date and to-date ,

I have tired with where between But it works only if I enter both from-date and to-date

public function searchCustomers(Request $request, CustomerProfile $user)
{
    $fromDate = $request->get('from_date');
    $toDate = $request->get('to_date');
    $user = $user->newQuery();

    if ($request->has('city')) {
        $user->where('city', $request->input('city'));
    }

    if ($request->has('from_date') && $request->has('to_date')) {
        $user->whereBetween('date_of_visit', [$fromDate, $toDate]);
    }
    $results = $user->get();

    return response()->json($results);
}

But sometimes I just want to search with only from-date, and sometimes I want to search with only to-date, and sometimes I want to search with both from date and to-date,

How can I get above output??

via Chebli Mohamed