Filament: Helper Text in Reactive Live Forms

When building reactive forms with options based on other field values, you can use helperText() with a callback function to show some text in case of no options.

In general, all Filament form methods support closures like this, so you can put custom logic.

Forms\Components\Radio::make('group_id')
    ->options(function (Get $get) {
        // options based on values from other fields
    })
    ->helperText(function(Component $component) {
        if (empty($component->getOptions())) {
            return 'Sorry, no groups for your criteria';
        }
    })
    ->live(),