public function loadManifest($file)
    {
        if (!isset(static::$manifests[$file])) {
            $path = realpath(static::$public . "/{$file}");

            if (! $path) {
                throw new InvalidArgumentException(
                    "Manifest {$file} does not exist"
                );
            }

            static::$manifests[$file] = json_decode(
                file_get_contents(
                    $path,
                    true
                )
            );
        }
        return static::$manifests[$file];
    }