"Undefined variable: sort"

You get undefined variable where?

When im the url that in the route

When you get an error it says error in file X at line Y This tells you if the issue is in the controller or in the view. Show the error dump

Undefined variable: sort (View: C:\xampp5\htdocs\myshop\resources\views\content\products.blade.php)

And do you use this same blade template from your unsorted controller?

The products.blade is unsorted, when click "sort" it should sort the products

You did not answer the question.

If you load this view without coming through the SortController then obviously $sort is not initialised. You need to pass $sort through from the other controller also.

Or do as I suggested initially and do it all in the one controller. There is no need for separate routes for sorted and unsorted.

But it loaded the sort with the view

 return view('content.products', compact('products', 'sort'));

Can u explain how to to pass $sort through from the other controller also?

Or how to do it one controller? this is my shop controller

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Categorie;
use App\Product;
use App\Order;
use Cart, Session;

class ShopController extends MainController
{
   public function categories(){
       
   self::$data['categories']=Categorie::all()->toArray();
   self::$data['title']=self::$data['title'].'| Shop Categories';

   return view('content.categories', self::$data);
   }
   
   public function products($category_url){
       
    Product::getProducts($category_url, self:: $data);
    return view ('content.products', self::$data);
   }
   
   public function item($category_url, $product_url){
       
       Product::getItem($product_url, self::$data);
     return view ('content.item', self::$data);
  
}


public function addToCart(Request $request){
    Product::addToCart($request['id']);
    
}
public function checkout(){
    $cartCollection= Cart::getContent();
    $cart=$cartCollection->toArray();
    sort($cart);
    self::$data['cart']=$cartCollection->toArray();
    self::$data['title']=self::$data['title'].'| Shop checkout';
    return view('content.checkout', self::$data);
    
}


public function updateCart(Request $request){
  Product::updateCart($request);
    
}
public function clearCart(){
    
    Cart::clear();
    return redirect('shop/checkout');
}

public function order(){
    
    if( ! Session::has('user_id') ){
        Session::flash('sm','You must sign in to place your order');
        return redirect('user/signin?rnTo=shop/checkout');
    }
    else{
        if (Cart::isEmpty() ){
            return redirect('shop');
            
        }
        else{
            Order::save_order();
            return redirect('shop');
        }
    }
}




}

I tried to use one controller:

   public function products($category_url, Request $request){
        Product::getProducts($category_url, self:: $data);
        if ($category1 = Categorie::where('url', '=', $category_url)->first()) {
           $sort = $request->get('sort', 'asc');
           $products = Product::where('categorie_id', $category1->getAttribute('id'))->orderBy('price', $sort)->get();
          $sort = $sort == 'asc' ? 'desc' : 'asc'; // to use in sort link
           return view('content.products', self::$data , compact('products', 'sort'));
       
        
   }
   }

this is the route:

Route::get('shop/{category_url}','ShopController@products');

this is link fromt the view:

    <a href="{{ url('shop/'.$category['url'])}}?sort=DESC" style="color:black"> High to low</a> |
    <a href="{{ url('shop/'.$category['url'])}}?sort=ASC" style="color:black">Low to high</a>

but when I click on that link the order is not changing.

You will have to debug the controller method and see if you are receiving the sort order and if that is making the desired difference to your query

what is self::$data ?

Can you try this:

return view('content.products', array_merge(self::$data, compact("sort","products")));