Cookbooks
PHP
Chapter 5. Good Coding Practices
Refactoring

PHP:
Refactoring

How to:

Let’s take a classic PHP snippet and apply some refactoring magic to it.

Before refactoring, our code might look like this:

function printOrderDetails($order) {
    foreach ($order as $item) {
        echo "Item: " . $item['name'];
        echo " - Price: " . $item['price'];
        echo "<br>";
    }
    
    if (!empty($order)) {
        echo "Total: " . array_sum(array_column($order, 'price'));
    }
}

But we can refactor this code to improve its clarity and modularity:

function printItem($item) {
    echo "Item: {$item['name']} - Price: {$item['price']}<br>";
}

function calculateTotal($order) {
    return array_sum(array_column($order, 'price'));
}

function printOrderDetails(array $order) {
    array_walk($order, 'printItem');

    if (!empty($order)) {
        echo "Total: " . calculateTotal($order);
    }
}

By breaking down the printOrderDetails function into smaller functions, our code becomes more readable and easier to debug.

Deep Dive

Refactoring has its roots in the smalltalk programming community of the early 1990s and was further popularized by Martin Fowler’s seminal book “Refactoring: Improving the Design of Existing Code” (1999). While refactoring can be applied to any programming language, PHP’s dynamic nature allows for some unique challenges and opportunities.

Alternatives to refactoring might include rewriting code from scratch, which is often riskier and more time-consuming. In the PHP ecosystem, tools like PHPStan and Rector can automatically spot and perform some refactoring operations, respectively. Implementation-wise, keeping refactorings small and testing extensively with unit tests are key practices to ensure successful refactoring without introducing bugs.

See Also

Organizing code into functions