CyclomaticComplexity (CC)

Emitted when a method has too many decision points (if, else, switch, for, while, catch, etc.).

<?php
public function process(string $type, array $data): array
{
    if ($type === 'article') {
        if (isset($data['draft'])) {
            if ($data['draft'] === true) {
                // ...
            } else {
                // ...
            }
        } elseif (isset($data['scheduled'])) {
            // ...
        }
    } elseif ($type === 'page') {
        if ($data['template'] === 'full') {
            // ...
        } elseif ($data['template'] === 'sidebar') {
            // ...
        }
    } elseif ($type === 'widget') {
        // ...
    }
    // CC = 15
}

Why this is bad

Hard to test: Need many test cases to cover all paths
Hard to read: Deep nesting obscures the logic
Bug prone: Easy to miss edge cases
Hard to modify: Adding new conditions increases complexity exponentially

How to fix

Replace conditionals with polymorphism using the Strategy pattern:

<?php
public function process(string $type, array $data): array
{
    $processor = $this->processorFactory->create($type);

    return $processor->process($data);
}

Each processor handles its own logic:

<?php
class ArticleProcessor implements ProcessorInterface
{
    public function process(array $data): array
    {
        // Only article-specific logic here
    }
}

Threshold

Level	CC Value
🍝 Piccolo	≤10
🍝🍝 Medio	11-15
🍝🍝🍝 Grande	16-20
🍝🍝🍝🍝 Mamma Mia!	21+