You can use the ??= operator to assign a value to a variable only if it's currently null or undefined. This can be handy for setting default values concisely.

$config ??= ['debug' => false, 'env' => 'production'];

// This assigns the array to $config only if $config is null or doesn't exist. It's equivalent to:

if (!isset($config)) {
    $config = ['debug' => false, 'env' => 'production'];
}