code: function readdirRecursivelySync(dir) {
    let results = [];
    const list = fs.readdirSync(dir);
    for (let file of list) {
      file = path.resolve(dir, file);
      const stat = fs.statSync(file);
      if (stat && stat.isDirectory()) {
        results = results.concat(readdirRecursivelySync(file));
      } else {
        results.push(file);
      }
    }
    return results;
  }
docs: Get all files in directory recursively, synchronously