1public function handle($request, Closure $next)
2{
3    // get response
4    $response = $next($request);
5    
6    // if response is JSON
7    if($response instanceof JsonResponse){
8
9        $current_data = $response->getData();
10
11        $current_data->userData = ['attach some additional user data'];
12
13        $response->setData($current_data);
14
15    }
16
17    return $response;
18}

1this middleware would perform its task after the request is handled by the application:
2
3<?php
4
5namespace App\Http\Middleware;
6
7use Closure;
8
9class AfterMiddleware
10{
11    public function handle($request, Closure $next)
12    {
13        $response = $next($request);
14
15        // Perform action
16
17        return $response;
18    }
19}