PHP Function Best Practices and Design Patterns

PHP best practices: follow camel case naming convention. Use type hints. Keep functions short and concise. Avoid side effects. Use documentation comments. Design pattern: Singleton pattern: ensures a single instance. Factory pattern: Create objects. Observer pattern: subscribe to events. Adapter mode: Compatible interface. Agent mode: Provides an agent.

PHP Function Best Practices and Design Patterns

Best Practices

1. Follow camel case naming: Use uppercase letters to distinguish words, such as myFunctionName().
2. Use type hints: Specify the types of function parameters and return values, for example function getSum(int $a, int $b): int {}.
3. Try to keep functions short and concise: The ideal length is 10-20 lines.
4. Avoid side effects: Functions should not accidentally modify external variables or perform other operations.
5. Use documentation comments: Describe the parameters, return values, and behavior of the function.

Design pattern

1. Singleton pattern: Ensures that only a single instance of a class can be accessed throughout the application.
2. Factory pattern: Create an object without specifying the exact concrete class.
3. Observer pattern: Allows objects to subscribe to events and react to them.
4. Adapter mode: Make incompatible interfaces compatible.
5. Proxy mode: Provide a proxy for another object or resource.

Practical case

Single case mode

class Database
{
    private static $instance;

    private function __construct() {}

    public static function getInstance(): Database
    {
        if (!isset(self::$instance)) {
            self::$instance = new Database();
        }

        return self::$instance;
    }
}

Factory mode

interface Vehicle
{
    public function start();
    public function stop();
}

class Car implements Vehicle
{
    public function start() { echo "Car started\n"; }
    public function stop() { echo "Car stopped\n"; }
}

class Truck implements Vehicle
{
    public function start() { echo "Truck started\n"; }
    public function stop() { echo "Truck stopped\n"; }
}

class VehicleFactory
{
    public static function createVehicle(string $type): Vehicle
    {
        switch ($type) {
            case 'car':
                return new Car();
            case 'truck':
                return new Truck();
            default:
                throw new InvalidArgumentException("Invalid vehicle type: $type");
        }
    }
}

// Usage
$car = VehicleFactory::createVehicle('car');
$car->start(); // Outputs "Car started"

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