How to use the node-video-lib.FragmentListIndexer function in node-video-lib

static index(name) {
        let fileName = path.join(config.mediaPath, name);
        let indexName = Indexer.getIndexName(name);
        let tmpName = Indexer.getTempName(name);

        let file = null;
        let index = null;

        try {
            file = fs.openSync(fileName, 'r');
            index = fs.openSync(tmpName, 'w');
            let movie = VideoLib.MovieParser.parse(file);
            let fragmentList = VideoLib.FragmentListBuilder.build(movie, config.fragmentDuration);
            VideoLib.FragmentListIndexer.index(fragmentList, index);
        } finally {
            if (file !== null) {
                fs.closeSync(file);
            }
            if (index !== null) {
                fs.closeSync(index);
            }
        }

        if (fs.existsSync(tmpName)) {
            try {
                Indexer.makeDirs(path.dirname(indexName));
                fs.renameSync(tmpName, indexName);
            } catch (ex) {
                fs.unlinkSync(tmpName);
                throw ex;

fs.openAsync(indexName, 'r').then((fd) => {
                req.index = fd;
                req.fragmentList = VideoLib.FragmentListIndexer.read(req.index);
            }).catch((err) => {
                let promise = Promise.resolve();