code: async function getFileList(dir, fileList) {
    return new Promise(async function (resolve, reject) {  
    fileList = fileList || [];
    var filesIndex = await io.getFiles(dir, null);   
    var files = io.absoluteFiles(filesIndex);
    files.forEach(function (file) {
      fileList.push(file);
    });
    resolve(fileList);
  });
  }
docs: Recursive function