BeforeRenderableIsRenderedEvent 

New in version 14.0

The event BeforeRenderableIsRenderedEvent is a replacement for the removed hook $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['ext/form']['beforeRendering'] .

The event BeforeRenderableIsRenderedEvent is dispatched before a renderable is rendered. This event allows a renderable to be modified before it is rendered or a form can be modified at runtime.

Example 

EXT:my_extension/Classes/EventListener/MyEventListener.php
<?php

declare(strict_types=1);

namespace MyVendor\MyExtension\EventListener;

use TYPO3\CMS\Core\Attribute\AsEventListener;
use TYPO3\CMS\Form\Event\BeforeRenderableIsRenderedEvent;

final readonly class MyEventListener
{
    #[AsEventListener(
        identifier: 'my-extension/before-renderable-is-rendered',
    )]
    public function __invoke(BeforeRenderableIsRenderedEvent $event): void
    {
        $renderable = $event->renderable;
        if ($renderable->getType() !== 'Date') {
            return;
        }
        $date = $event->formRuntime[$renderable->getIdentifier()];
        if ($date instanceof \DateTime) {
            $event->formRuntime[$renderable->getIdentifier()] = $date->format('Y-m-d');
        }
    }
}
Copied!

API 

class BeforeRenderableIsRenderedEvent
Fully qualified name
\TYPO3\CMS\Form\Event\BeforeRenderableIsRenderedEvent

Listeners to this Event will be able to modify the renderable before it is rendered.

public renderable
public formRuntime