Cart with login in laravel 5.7 - laravel

Question

I am implement shopping cart with login & witout login i am using cart package from laravel but it will stored cart item on local storage now i want to login and add cart item in database. When i am not login then item adds in local storage but when i am login then items add in database i am confuse. how i am implement I am sharing my code that i am developed need solutions
Controller:
public function add_to_cart(Request $req)
{
$userId=Session::get('userid');
$qty=$req->qty;
$product_id=$req->product_id;
$product_info=DB::table('product_details')
->join('subcategory','subcategory.sub_id','=','product_details.sub_id')
->select('subcategory.image','subcategory.name_of_subcategory','product_details.*')
->where('product_details.product_id',$product_id)->first();
$sub_id=$product_info->sub_id;
//dd($product_info);
Cart::add(array(
'id'=>$product_info->product_id,
'name'=>$product_info->name_of_subcategory,
'price'=>$product_info->price,
'qty'=>$qty,
'options'=>array('image' =>$product_info->image,'description'=>$product_info->description_of_product)
));
if($userId)
{
$content=\Cart::Content();
}
// $content=\Cart::Content();
// dd($content);
//$data = DB::select('select * from product_details where sub_id = ?',[$sub_id]);
//return view('productdetails',['data'=>$data]);
return view('cart');
}
blade
#extends('layout.header')
#section('content')
<?php
$contents=\Cart::Content();
?>
<div class="container mt-5">
<table id="cart" class="table table-hover table-condensed">
<thead>
<tr>
<th>Product</th>
<th>Price</th>
<th>Quantity</th>
<th class="text-center">Subtotal</th>
<th></th>
</tr>
</thead>
<tbody>
#foreach($contents as $v_contents)
<tr>
<td data-th="Product">
<div class="row">
<div class="col-sm-4 hidden-xs"><img src="{{asset('images/'.$v_contents->options->image)}}" alt="..." class="img-responsive"/ height="100" width="100"></div>
<div class="col-sm-8">
<h4 class="nomargin">{{$v_contents->name}}</h4>
<p>{{$v_contents->options->description}}</p>
</div>
</div>
</td>
<td data-th="Price">{{$v_contents->price}}</td>
<td data-th="Quantity">
<div class="plus-minus" style="width:150px; ">
<div class="input-group">
<span class="input-group-btn">
<button type="button" class="btn btn-default btn-number" id="subs" >
<span class="fa fa-minus"></span>
</button>
</span>
<input type="text" id="qty" name="qty" class="form-control input-number" value="{{$v_contents->qty}}" min="1" max="10">
<span class="input-group-btn">
<button type="button" class="btn btn-default btn-number" data-type="plus" id="adds">
<span class="fa fa-plus"></span>
</button>
</span>
</div>
<input type="hidden" name="product_id" id="product_id" value="{{ $v_contents->rowId}}">
</div>
</td>
<td data-th="Subtotal" class="text-center">{{ $v_contents->total}}</td>
<td class="actions" data-th="">
<a class="btn btn-danger btn-sm" href="{{ URL::to('/delete-to-cart/'.$v_contents->rowId)}}"><i class="fa fa-trash-o"></i></a>
</td>
</tr>
#endforeach
</tbody>
<tfoot>
<!-- <tr class="visible-xs">
<td class="text-center"><strong>Total 1.99</strong></td>
</tr> -->
<tr>
<td><i class="fa fa-angle-left"></i> Continue Shopping</td>
<td colspan="2" class="hidden-xs"></td>
<td class="hidden-xs text-center"><strong>Total {{\Cart::subtotal()}}</strong></td>
<td>Checkout <i class="fa fa-angle-right"></i></td>
</tr>
</tfoot>
</table>
</div>
<script type="text/javascript">
/*$('#adds').click(function add() {
var $qty = $("#qty");
var a = $qty.val();
a++;
$("#subs").prop("disabled", !a);
$qty.val(a);
});
$("#subs").prop("disabled", !$("#qty").val());
$('#subs').click(function subst() {
var $qty = $("#qty");
var b = $qty.val();
if (b >= 1) {
b--;
$qty.val(b);
}
else {
$("#subs").prop("disabled", true);
}
});*/
</script>
<script>
$(document).ready(function(){
$(document).on('click', '#adds', function(e) {
var qty = $('#qty').val();
var product_id=$('#product_id').val();
//alert(qty);
e.preventDefault()
$.ajaxSetup({
headers: {
'X-CSRF-TOKEN': $('meta[name="_token"]').attr('content')
}
});
jQuery.ajax({
url: "{{ url('/increment') }}",
method: 'get',
data: {
qty: qty,id:product_id
},
success: function(result){
jQuery('#qty').val(result.qty);
}});
});
});
</script>
<script>
$(document).ready(function(){
$(document).on('click', '#subs', function(e) {
var qty = $('#qty').val();
var product_id=$('#product_id').val();
//alert(qty);
e.preventDefault()
$.ajaxSetup({
headers: {
'X-CSRF-TOKEN': $('meta[name="_token"]').attr('content')
}
});
jQuery.ajax({
url: "{{ url('/decrement') }}",
method: 'get',
data: {
qty: qty,id:product_id
},
success: function(result){
jQuery('#qty').val(result.qty);
}});
});
});
</script>
#endsection