When adding content to json file php error occurs

I’m learning php and started following a youtube video for a project.

When i accept contents from my json file and code it to add new contents to it, an error occurs.

Error-

Warning: Undefined variable $json_encode in /Users/montekkundan/Downloads/coding/php/newtodo.php on line 16

Fatal error: Uncaught Error: Value of type null is not callable in /Users/montekkundan/Downloads/coding/php/newtodo.php:16 Stack trace: #0 {main} thrown in /Users/montekkundan/Downloads/coding/php/newtodo.php on line 16

php code-

<?php
// echo "<pre>";
// var_dump($_POST);
// echo "</pre>";

$todoname = $_POST['todoname'] ?? "";
$todoname = trim($todoname);

if($todoname) {
  $json = file_get_contents('todo.json');
  $jsonArray = json_decode($json, true);
  $jsonArray[$todoname] = ['completed' => false];
  // echo "<pre>";
  // var_dump($jsonArray);
  // echo "</pre>";
 file_put_contents('todo.json', $json_encode($jsonArray, JSON_PRETTY_PRINT)) ;
}
?>

>Solution :

Try to change
file_put_contents('todo.json', $json_encode($jsonArray, JSON_PRETTY_PRINT));
to file_put_contents('todo.json', json_encode($jsonArray, JSON_PRETTY_PRINT));
that’s because you are trying to call json_encode variable, json_encode is not a variable.