Registering Filters

    Once you have defined a filter, you are ready to attach it to a resource. Each resource generated by Nova contains a filters method. To attach a filter to a resource, you should simply add it to the array of filters returned by this method:

    /**
     * Get the filters available for the resource.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return array
     */
    public function filters(Request $request)
    {
        return [
            new Filters\UserType,
        ];
    }