App\Ninja\Datatables\RecurringInvoiceDatatable::columns PHP Method

    public function columns()
    {
        return [['frequency', function ($model) {
            $frequency = strtolower($model->frequency);
            $frequency = preg_replace('/\\s/', '_', $frequency);
            return link_to("invoices/{$model->public_id}", trans('texts.freq_' . $frequency))->toHtml();
        }], ['client_name', function ($model) {
            return link_to("clients/{$model->client_public_id}", Utils::getClientDisplayName($model))->toHtml();
        }, !$this->hideClient], ['start_date', function ($model) {
            return Utils::fromSqlDate($model->start_date);
        }], ['end_date', function ($model) {
            return Utils::fromSqlDate($model->end_date);
        }], ['amount', function ($model) {
            return Utils::formatMoney($model->amount, $model->currency_id, $model->country_id);
        }]];
    }