PHP data became empty after json_encode - php

Question

I have the following php code. I am able to get the value stored in my variable and printed. But after json_encode, the value became 'empty'. Is there a bug in json_encode ? I am using Php 7.2 on ubuntu 18
<?php
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL,'https://www.thestar.com.my/rss/news/nation');
curl_setopt($ch, CURLOPT_HEADER, false);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$xml = curl_exec($ch);
curl_close($ch);
$rss = simplexml_load_string($xml);
$cnt = count($rss->channel->item);
$items = array();
$items[0]['title'] = $rss->channel->item[0]->title;
$items[0]['url'] = $rss->channel->item[0]->link;
echo $items[0]['title'] . PHP_EOL;
echo $items[0]['url'] . PHP_EOL;
echo json_encode($items) . PHP_EOL;
?>
See the output below. What is wrong with the json_encode ? Why after the json_encode, the title became empty ?
Sabah updates SOPs for places of worship and childcare centres
https://www.thestar.com.my/news/nation/2021/06/13/sabah-updates-sops-for-places-of-worship-and-childcare-centres
[{"title":{"0":{}},"url":{"0":"https:\/\/www.thestar.com.my\/news\/nation\/2021\/06\/13\/sabah-updates-sops-for-places-of-worship-and-childcare-centres"}}]

Answer 1

json_encode produces an empty object tag ({}) when passed PHP objects that do not implement JsonSerializable or contain public member variables.
You pass it \SimpleXMLElement nodes, not strings.
In your echo it just shows because the XML entities implement __toString() which echo invokes.
Either do that aswell or cast it to (string):
<?php
$rss = simplexml_load_string($xml);
$items = array();
$items[0]['title'] = $rss->channel->item[0]->title->__toString();
$items[0]['url'] = (string) $rss->channel->item[0]->link;
echo json_encode($items) . PHP_EOL;
?>

Answer 2

Thanks..Got it with
$items[0]['title'] = $rss->channel->item[0]->title->__toString();