Post: Refatorando código com Extract Method

example1.php

<?php

$products = [
    'Geladeira' => 1500.99,
    'Fogão'     => 350,
    'Celular'   => 1190.90
];

function before_add_shopping_cart(array $products): array {
    $output = [
        'amount' => count($products),
        'total'  => 'R$ ' . number_format(array_sum($products), 2, ',', '.')
    ];

    $output['items'] = array_map(function($value): string {
        return 'R$ ' . number_format($value, 2, ',', '.');
    }, $products);

    // Send an email to sales team
    $to      = '[email protected]';
    $subject = 'the subject';
    $message = 'hello';
    $headers = 'From: [email protected]' . "\r\n" .
        'Reply-To: [email protected]' . "\r\n" .
        'X-Mailer: PHP/' . phpversion();

    mail($to, $subject, $message, $headers);

    return $output;
}