Guard Clause

RefactoringFirstStep.php

<?php

public function markActiveNode($navigation, $currentUrl)
{
    if(empty($navigation['nodes']) or !is_array($navigation['nodes']) {
        return $navigation;
    }
    
    foreach ($navigation['nodes'] as $node) {
        $node['isActive'] = false;
        if(!empty($node['url'])) {
            if($node['isVisible']) {
                $node['isActive'] = ($node['url'] === $currentUrl);
            }
        }
    }
    
    return $navigation;
}