Mastering Conditional Logic in Laravel with `when()` and `unless()` Methods: Real-Life Examples

Laravel, a renowned PHP framework, boasts an elegant syntax and powerful features. Introduced in Laravel 11.35.0, the when() and unless() methods (part of the Conditionable trait) offer a more concise and efficient approach to conditional logic, significantly improving code readability and maintainability. This article explores practical applications of these methods in real-world Laravel scenarios.

1. Dynamic Role Assignment Based on User Input

Consider a user registration form where users select a role. Post-registration, different permissions are assigned based on the chosen role.

Without when():

if ($request->has('role')) {
    $user->assignRole($request->input('role'));
}

With when():

$user->when($request->has('role'), function ($user) use ($request) {
    $user->assignRole($request->input('role'));
});

The when() method neatly encapsulates role assignment, executing only when a role is provided.

2. Dynamic Validation Rules

In a form, certain fields might require validation only under specific conditions. For instance, the email field is mandatory only if the user opts into a newsletter.

Without when():

$rules = [
    'email' => 'nullable',
];

if ($request->has('newsletter')) {
    $rules['email'] = 'required|email';
}

$request->validate($rules);

With when():

$request->when($request->has('newsletter'), function () use ($request) {
    $request->validate([
        'email' => 'required|email',
    ]);
});

This cleaner approach leverages when() for conditional validation.

3. Conditional Data Merging

In e-commerce, discounts might apply only with a valid coupon code. Let's dynamically merge discount data.

Without when():

$data = [
    'total_price' => $cart->totalPrice(),
];

if ($request->has('coupon_code')) {
    $coupon = Coupon::where('code', $request->input('coupon_code'))->first();
    if ($coupon) {
        $data['discount'] = $coupon->discount_amount;
    }
}

return response()->json($data);

With when():

$data = [
    'total_price' => $cart->totalPrice(),
];

$data = $data->when($request->has('coupon_code'), function ($data) use ($request) {
    $coupon = Coupon::where('code', $request->input('coupon_code'))->first();
    if ($coupon) {
        $data['discount'] = $coupon->discount_amount;
    }
    return $data;
});

return response()->json($data);

This demonstrates a more streamlined, chainable approach to conditional discount application.

4. Simplifying User Status Logic

Sending different messages based on user activation status can be simplified using unless().

Without unless():

if (!$user->isActive()) {
    return "Your account is inactive. Please contact support.";
} else {
    return "Welcome back!";
}

With unless():

return $user->unless($user->isActive(), function () {
    return "Your account is inactive. Please contact support.";
})->otherwise(function () {
    return "Welcome back!";
});

unless() condenses the conditional logic into a single, readable return statement.

5. Combining when() and unless()

For complex scenarios, combine when() and unless() to manage various user types (admin, guest, etc.) and display appropriate content.

$variable->when($user->isAdmin(), function ($variable) {
    return $variable->adminDashboard();
})->unless($user->isAdmin(), function ($variable) {
    return $variable->guestDashboard();
});

Further Examples (Briefly Summarized):

The article continues with similar concise examples demonstrating the use of when() and unless() in:

• Payment Gateway Integration: Selecting payment logic based on user's chosen method.
• Real Estate Price Calculation: Applying discounts based on first-time buyer status or promo codes.
• Medical Appointments: Adjusting payment based on insurance coverage.
• Bitcoin Price Adjustment: Adding fees based on market volatility.
• E-commerce Product Availability: Determining shipping fees based on location.
• Medical Treatment Plans: Assigning treatment plans based on patient conditions.

These examples highlight the versatility and elegance of Laravel's when() and unless() methods across diverse applications. By utilizing these methods, developers can write cleaner, more maintainable, and more readable Laravel code.

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