How can you implement custom Twig filters in Symfony?

Custom Twig filters allow developers to extend the Twig templating engine with new functionality. This enables you to create reusable and specific formatting functions within your templates.

To implement a custom filter, follow these steps:

1. Create a Service: Define a service class that contains the method for your filter.
2. Register the Service: In your service configuration, register the service and tag it as a Twig filter.
3. Use in Templates: Call your new filter in Twig templates.

Example of a custom filter:

namespace App\Twig;  
use Twig\Extension\AbstractExtension;  
use Twig\TwigFilter;  
class AppExtension extends AbstractExtension {  
    public function getFilters() {  
        return [new TwigFilter('custom_filter', [$this, 'customFilterMethod'])];  
    }  
    public function customFilterMethod($value) {  
        return strtoupper($value);  
    }  
}