Are there any common pitfalls to avoid when implementing object-oriented design in PHP?

One common pitfall to avoid when implementing object-oriented design in PHP is tightly coupling classes together, which can make the code harder to maintain and test. To solve this, use dependency injection to inject dependencies into classes rather than hardcoding them. 

// Before: Tightly coupled classes
class Database {
    public function connect() {
        return 'Connected to database';
    }
}

class User {
    private $db;

    public function __construct() {
        $this->db = new Database();
    }
}

// After: Using dependency injection
class Database {
    public function connect() {
        return 'Connected to database';
    }
}

class User {
    private $db;

    public function __construct(Database $db) {
        $this->db = $db;
    }
}

// Usage
$db = new Database();
$user = new User($db);

Keywords

inheritance encapsulation polymorphism SOLID principles dependency injection

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