Early Return Pattern

A common pattern in functions is to check for invalid conditions first and return early:

function processUserData($userData) {
    // Check if data is missing
    if (empty($userData)) {
        return "Error: No user data provided";
    }
    
    // Check if required fields exist
    if (!isset($userData['email'])) {
        return "Error: Email field is required";
    }
    
    // If we get here, the data is valid, so we can process it
    // ...process the data...
    return "Data processed successfully";
}
                

This pattern makes your code cleaner by handling error cases upfront.

Guard Clauses

Similar to early returns, guard clauses protect the main logic of your function:

function calculateDiscount($totalAmount, $customerType) {
    // Guard clauses
    if ($totalAmount <= 0) {
        return 0;
    }
    
    if ($customerType === 'premium') {
        return $totalAmount * 0.2; // 20% discount
    }
    
    if ($totalAmount > 1000) {
        return $totalAmount * 0.1; // 10% discount
    }
    
    // Default case
    return $totalAmount * 0.05; // 5% discount
}
                

Null Checking

When working with data that might be null, it's common to check before proceeding:

$user = getUserById($userId); // This function might return null

if ($user !== null) {
    // Safe to access user properties
    echo "Hello, {$user->name}!";
}
                

Multiple Conditions with Logical Operators

You can combine multiple conditions using logical operators:

// AND operator (&&): Both conditions must be true
if ($age >= 18 && $hasParentalConsent) {
    echo "You can proceed.";
}

// OR operator (||): At least one condition must be true
if ($isAdmin || $isModerator) {
    echo "You have access to the control panel.";
}

// NOT operator (!): Inverts the truth value
if (!$isLoggedIn) {
    echo "Please log in to continue.";
}