Feature request: a displayIf(callable) for Fields.

[armellin]

It would be nice to have a displayIf(callable) method for Fields, similar to the one used for Actions.

It would be useful, in detail, edit, and new, to set a criterion for displaying the field according to the properties of the Entity, e.g.:

yield TextField::new('reason')->displayIf(fn (?Order $entity) => $entity?->isCancelled());

The implementation could be:

// src/Field/FieldTrait.php

public function displayIf(callable $callable): self
{
    $this->dto->setDisplayCallable($callable);

    return $this;
}

// src/Dto/FieldDto.php

private $displayCallable;

public function setDisplayCallable(callable $displayCallable): void
{
    $this->displayCallable = $displayCallable;
}

public function shouldBeDisplayedFor(EntityDto $entityDto): bool
{
    return null === $this->displayCallable || \call_user_func($this->displayCallable, $entityDto->getInstance());
}

// src/Factory/FieldFactory.php

public function processFields(EntityDto $entityDto, FieldCollection $fields, string $currentPage): void

    ..............

    if (Crud::PAGE_INDEX !== $currentPage && false === $fieldDto->shouldBeDisplayedFor($entityDto)) {
        $fields->unset($fieldDto);
        continue;
    }

    ..............

}