How do traits work in PHP? Why are they needed?

In PHP, traits are a mechanism for code reuse that lets you share methods between multiple unrelated classes without using inheritance.

How Traits Work

A trait is like a partial class that contains methods (and sometimes properties) you want to reuse in multiple classes.
You cannot instantiate a trait on its own — instead, you import it into a class using the use keyword.

Example:

trait Logger {
    public function log($message) {
        echo "[LOG]: $message\n";
    }
}

class User {
    use Logger;
    public function createUser() {
        $this->log("User created");
    }
}

class Product {
    use Logger;
    public function addProduct() {
        $this->log("Product added");
    }
}

$user = new User();
$user->createUser();

$product = new Product();
$product->addProduct();

Why Traits Are Needed

PHP does not support multiple inheritance.
This means a class can only extend one other class.

Problem:
If you have shared logic (like logging, caching, or authentication) that multiple classes need, you can’t simply inherit from multiple parent classes.

Solution:
Traits let you inject those common methods into any number of classes, without affecting the class hierarchy.

Key Points About Traits

1. Multiple traits can be used in the same class: use TraitA, TraitB;
2. Conflict resolution
   If two traits have the same method name, you can choose which one to use: use TraitA, TraitB { TraitA::methodName insteadof TraitB; TraitB::methodName as methodFromB; }
3. Traits can have properties (though it’s less common): trait HasName { public $name; }
4. Traits can call other methods in the class they’re used in.

✅ When to Use Traits

• When you want to share common methods between unrelated classes.
• When you don’t want to force inheritance.
• For mix-in behavior like logging, validation, caching, authentication, etc.