Refactoring Techniques in PHP | CodeSignal Learn

Refactoring Techniques in PHP | CodeSignal Learn

Imagine having a complex map. Refactoring transforms it into simpler directions. Our code gets rearranged to make it more readable and efficient without altering what it does. Let's consider a small code snippet before and after refactoring:

PHP

// Before refactoring
function calculate($total, $quantity) {
    $price = $total / $quantity;
    $tax = $price * 0.2;
    $totalPrice = $price + $tax;
    return $totalPrice;
}

// After refactoring
function calculateTotalPrice($total, $quantity) {
    $price = calculatePrice($total, $quantity);
    $tax = calculateTax($price);
    return $price + $tax;
}

function calculatePrice($total, $quantity) {
    return $total / $quantity;
}

function calculateTax($price) {
    return $price * 0.2;
}

Both versions of the code do the same thing, but the latter is simpler and easier to understand!

Imagine a large recipe for a complete breakfast. The Extract Method technique is like having separate recipes for eggs, toast, coffee, etc., instead of one large recipe. Take a look at this code:

PHP

// Before refactoring
function greetUser($username) {
    $username = strtolower(trim($username)); // Prepare the username
    $message = "Hello, " . $username . "!"; // Prepare the message
    return $message; // Return the prepared message
}

// After refactoring
function cleanUsername($username) {
    return strtolower(trim($username)); // Returns a cleaned version of the username
}

function greetUser($username) {
    $username = cleanUsername($username); // Clean the username
    $message = "Hello, " . $username . "!"; // Prepare and return the message
    return $message;
}

Here, we moved the username preparation from greetUser into its own function, cleanUsername. Nice and tidy!

Clear method names make it easy to understand our code, just as clear street names make navigating a city more accessible. Let's have a look at renaming a method:

PHP

// Before refactoring
function fx($x) {
    return 3.14 * ($x * $x); // Calculates a value that is pi times the square of x
}

// After refactoring
function calculateCircleArea($radius) {
    return 3.14 * ($radius * $radius); // Calculates the area of a circle with a given radius
}

Renaming the function fx to calculateCircleArea makes it easier to understand its purpose.

A Substitute Algorithm involves replacing a part of the code (an algorithm) with a simpler one, analogous to discovering a faster route to school. Here's an example:

PHP

// Before refactoring
function findSmallest($numbers) {
    $smallest = PHP_INT_MAX;
    foreach ($numbers as $num) {
        if ($num < $smallest) {
            $smallest = $num;
        }
    }
    return $smallest;
}

// After refactoring
function findSmallest($numbers) {
    return min($numbers); // Returns the smallest number from 'numbers'
}

Using min($numbers) performs the same job as our previous function but with less code.