Conditional layout templates

I want to use layout templates instead of doing this:

PHP Code:

            echo view('html_top', $vars);
            echo view($view, $vars);
            echo view('html_bottom', $vars); 


The think is - my application handles views differently if they are AJAX calls or not. If they are AJAX it returns a JSON with the view inside of it. If not, it will return the view with top html and bottom html. For this to work I have created a View library, like so:

PHP Code:

    public function view($view, $vars = array())
    {
        $request = service('request');
        $siteConfig = config('Site');
        $session = service('session');

        $page_title = $this->url_to_title($vars);

        if ($request->isAJAX()) {
            if (isset($vars['json'])) {
                $data['manipulateDom'] = $vars['json'];
            }

            $data['title'] = $page_title;

            $vars['logged_in']  = $session->logged_in;
            $vars['site_name'] = $siteConfig->name;
            $data['content'] = view($view, $vars);

            echo json_encode($data);
        } else {
            $vars['page_title'] = $page_title;
            $vars['logged_in']  = $session->logged_in;
            $vars['site_name'] = $siteConfig->name;
            
            echo view('html_top', $vars);
            echo view($view, $vars);
            echo view('html_bottom', $vars);
        }
    } 


But view templates are not triggered from the controller, but from the view. Is there any way of echoing a template in a controller with another view inside of it? I guess I can pass $request->isAJAX() to the view and do something like this:

PHP Code:

<?php if ($isAJAX): ?>
<?= $this->extend('default') ?>
<?php endif; ?>

But it doesn't feel right, and I would then have to put it in all views. I rather do it from the controller or a lib.