<?php

namespace Drupal\hello\Controller;

use Drupal\Component\Serialization\Json;
use Drupal\Core\Controller\ControllerBase;
use Drupal\Core\Link;
use Drupal\Core\Url;

class NodeListController extends ControllerBase {

  public function content($nodetype = NULL) {
    $storage = $this->entityTypeManager()->getStorage('node');
    $query = $storage->getQuery();
    if ($nodetype) {
      $query->condition('type', $nodetype);
    }
    $nids = $query->pager(10)->execute();
    $nodes = $this->entityTypeManager()->getStorage('node')->loadMultiple($nids);
    $items = [];
    foreach ($nodes as $node) {
      $items[] = $node->toLink();
    }
    $list = [
      '#theme' => 'item_list',
      '#items' => $items,
    ];
    $pager = [
        '#type' => 'pager'
    ];
    return [$list, $pager];
  }

}