How to Use Casts Inside a Laravel Trait

To add to $casts inside a trait, you'll first need to implement the initialize prefix to the current name of the trait. Here's an example with an Archivable trait I recently implemented in a course.

trait Archivable
{
    public function initializeArchivable()
    {
        //
    }
}

This method is invoked before anything else happens within your model's setup, so it's the perfect time to merge in any additional casts your trait needs to add to the model it's being applied to.

To do that, simply use the mergeCasts method.

trait Archivable
{
    public function initializeArchivable()
    {
        $this->mergeCasts([
            'archived_at' => 'datetime'
        ]);
    }
}

And that's it. Your casts will be applied to the model, and any casts already defined will stay put.