Null Coalescing Operator in PHP

Consider the following code:

php<?php
  if (isset($arr['test'])) {
    $elem = $arr['test'];
  } else {
    $elem = 'empty';
  }
?>

This code can be rewritten using the ternary operator:

php<?php
  $elem = isset($arr['test']) ? $arr['test'] : 'empty';
?>

However, both the first and second versions of the code cause some inconvenience. To simplify such constructs, the null coalescing operator was invented, represented by the command ??. Let's rewrite our code using this operator:

php<?php
  $elem = $arr['test'] ?? 'empty';
?>

php<?php
  $user = ['name' => 'john', 'age' => 30];
  
  if (isset($user['name'])) {
    $name = $user['name'];
  } else {
    $name = 'unknown';
  }
?>