Feature Request: Enable dependsOn for Panel Field to Support Dynamic Fields

[nastoychev]

Summary
Currently, Laravel Nova supports dependsOn for individual fields, allowing developers to conditionally show/hide fields based on user input. However, there is no built-in way to apply this behavior to Panels, which would be highly beneficial for dynamically generating form sections.

I propose extending the Panel class to support dependsOn, enabling the creation of dynamic field groups based on form values.

Use Case
Consider a scenario where the available form fields depend on a selected customer. Ideally, we should be able to dynamically modify the fields inside a Panel when the customer field changes.

Desired Usage
With dependsOn support, we should be able to use a Panel like this:

Panel::make(name:'Dynamic Fields', fields: [])
    ->dependsOn(['customer'], function (Panel $panel, NovaRequest $request, FormData $formData): void {
        if (!empty($formData->get('customer'))) {
            $panel->setFields([
                Text::make('Name')->rules(['required', 'string', 'max:255']),
                ...$this->getCustomerFields($formData->get('customer')),
            ]);
        }
    });

• When the customer field changes, the Panel dynamically updates to include fields relevant to the selected customer.
• This improves form flexibility and avoids rendering unnecessary fields upfront, reducing clutter and improving user experience.