yii\web\AssetBundle::registerAssetFiles PHP Method

    public function registerAssetFiles($view)
    {
        $manager = $view->getAssetManager();
        foreach ($this->js as $js) {
            if (is_array($js)) {
                $file = array_shift($js);
                $options = ArrayHelper::merge($this->jsOptions, $js);
                $view->registerJsFile($manager->getAssetUrl($this, $file), $options);
            } else {
                if ($js !== null) {
                    $view->registerJsFile($manager->getAssetUrl($this, $js), $this->jsOptions);
                }
            }
        }
        foreach ($this->css as $css) {
            if (is_array($css)) {
                $file = array_shift($css);
                $options = ArrayHelper::merge($this->cssOptions, $css);
                $view->registerCssFile($manager->getAssetUrl($this, $file), $options);
            } else {
                if ($css !== null) {
                    $view->registerCssFile($manager->getAssetUrl($this, $css), $this->cssOptions);
                }
            }
        }
    }

    /**
     * @inheritdoc
     */
    public function registerAssetFiles($view)
    {
        if ($this->language !== null) {
            $this->js[] = 'select2_locale_' . $this->language . '.js';
        }
        $view->registerJs(<<<JS
\t\t\tfunction formatResult(item) {
\t\t\t\t      if(!item.id) {
\t\t\t\t        // return `text` for optgroup
\t\t\t\t        return item.text;
\t\t\t\t      }
\t\t\t\t      // return item template
\t\t\t\t      return '<i>' + item.text + '</i>';
\t\t\t\t    };
\t\t
\t\t    function formatSelection(repo) {
\t\t\t\t\t//repo.selected =true;
\t\t      // return selection template
\t\t      //return '<b>' + item.text + '</b>';
\t\t        return repo.full_name || repo.text;
    \t\t};
JS
, \yii\web\View::POS_READY);
        parent::registerAssetFiles($view);
    }