code: protected function initClientOptions()
      {
          $options = $this->clientOptions;
          foreach ($options as $key => $value) {
              if (
                  !$value instanceof JsExpression
                  && in_array($key, [
                      'oncomplete', 'onincomplete', 'oncleared', 'onKeyUp', 'onKeyDown', 'onBeforeMask',
                      'onBeforePaste', 'onUnMask', 'isComplete', 'determineActiveMasksetIndex',
                  ], true)
              ) {
                  $options[$key] = new JsExpression($value);
              }
          }
          $this->clientOptions = $options;
      }
docs: Initializes client options.