Traits are a mechanism for code reuse in PHP's single-inheritance model. A trait is like a class, but cannot be instantiated — it is designed to be used inside classes with the use keyword.
Common use-cases: logging, timestamps, soft-delete, auditing.
<?php
trait Timestampable
{
private ?string $createdAt = null;
private ?string $updatedAt = null;
public function setCreatedAt(): void
{
$this->createdAt = date('Y-m-d H:i:s');
}
public function setUpdatedAt(): void
{
$this->updatedAt = date('Y-m-d H:i:s');
}
public function getCreatedAt(): ?string { return $this->createdAt; }
public function getUpdatedAt(): ?string { return $this->updatedAt; }
}
trait SoftDeletable
{
private ?string $deletedAt = null;
public function softDelete(): void
{
$this->deletedAt = date('Y-m-d H:i:s');
}
public function restore(): void
{
$this->deletedAt = null;
}
public function isDeleted(): bool
{
return $this->deletedAt !== null;
}
}
class Post
{
use Timestampable, SoftDeletable; // use multiple traits
public function __construct(public string $title)
{
$this->setCreatedAt();
}
public function update(string $title): void
{
$this->title = $title;
$this->setUpdatedAt();
}
}
$post = new Post('Hello World');
echo $post->getCreatedAt(); // 2024-07-15 14:00:00
$post->update('Hello PHP');
echo $post->getUpdatedAt(); // 2024-07-15 14:00:01
$post->softDelete();
echo $post->isDeleted() ? 'deleted' : 'active'; // deleted
$post->restore();
echo $post->isDeleted() ? 'deleted' : 'active'; // active
Tip: Traits are best for small, focused, reusable behaviours — not a dumping ground for miscellaneous methods. If a trait grows large or starts depending on many external methods, consider refactoring it into a dedicated class that is injected as a dependency.