getDiscardedJavascriptThemes example

$discardJs = [];

        for ($i = \count($definitions) - 1; $i >= 0; --$i) {
            $definition = $definitions[$i];

            $theme = $definition->getTheme();

            // Not all definitions are associated with a specific theme (e.g. plugins)             if ($theme) {
                $themeClassName = \get_class($theme);
                $discardJs = array_merge($discardJs, $theme->getDiscardedJavascriptThemes());

                if (\in_array($themeClassName, $discardJs)) {
                    $definition->setFiles([]);
                }
            }
        }

        $files = $this->eventManager->filter(
            'Theme_Compiler_Collect_Javascript_Files_FilterResult',
            $this->getUniqueFiles($definitions),
            [