TypeError: Ht.apply is not a function when using customButtons with a click handler

[kennyhorna]

Hello,

I'm having trouble implementing customButtons with a click handler in a Filament v4 widget. Despite ensuring all assets are loaded correctly and providing a valid function to the click property, the underlying vkurko/calendar library consistently throws a:

TypeError: Ht.apply is not a function on the frontend.

Environment:

• Laravel Version: 12.x
• Filament Version: 4.x
• guava/calendar Version: 2.x
• PHP: 8.3

Minimal Reproducible Example (VenueBookingControlWidget.php):

This is the simplified widget code that still produces the error. The goal is for the custom buttons to call a Livewire method.

<?php

namespace App\Filament\Widgets;

use Filament\Support\RawJs;
use Guava\Calendar\Filament\CalendarWidget;

class VenueBookingControlWidget extends CalendarWidget
{
    public string $activeView = 'resourceTimeGridWeek';

    public function setView(string $view): void
    {
        $this->activeView = $view;
    }

    public function getOptions(): array
    {
        return [
            'customButtons' => [
                'dayView' => [
                    'text' => 'Día',
                    'click' => RawJs::from("function() { \$wire.setView('resourceTimeGridDay'); }"),
                    'class' => \$this->activeView === 'resourceTimeGridDay' ? 'ec-active' : '',
                ],
                'weekView' => [
                    'text' => 'Semana',
                    'click' => RawJs::from("function() { \$wire.setView('resourceTimeGridWeek'); }"),
                    'class' => \$this->activeView === 'resourceTimeGridWeek' ? 'ec-active' : '',
                ],
            ],
            'headerToolbar' => [
                'start' => 'prev',
                'center' => 'title',
                'end' => 'next today dayView,weekView',
            ],
            'view' => $this->activeView,
            'allDaySlot' => false,
            'locale' => 'es',
        ];
    }
    
    // getEvents, etc.
}

Troubleshooting Steps Taken:

Confirmed all CSS and JS assets (including vendor/guava/calendar/resources/js/calendar.js) are correctly imported and bundled with Vite.

Confirmed the widget's FilamentAsset::register() and .viteTheme() setup is correct.

The error persists even when the click handler is simplified to RawJs::from("function() { alert('test'); }").

The error occurs regardless of whether the click handler content is a simple string or a full function definition, suggesting an issue in how the options are processed.

It seems like the click property is not being correctly interpreted as a function by the time it reaches the vkurko/calendar initialization script. Any insight would be greatly appreciated.

Thank you!