String base64FileInfo = fileInfotoString; if StrUtilisNotEmptybase64FileInfo String fileInfoStr = Base64decodeStrbase64FileInfo;

以下是将上述Java代码转换为JavaScript代码的示例：

let base64FileInfo = fileInfo.toString();
if (base64FileInfo) {
  let fileInfoStr = Base64.decode(base64FileInfo);
  let fileItems = fileInfoStr.split("&");
  if (fileItems.length >= 2) {
    let fileToken = fileItems[0];
    let fileName = fileItems[1];
    fileToken = fileToken.replace(/\\|\//g, "■");
    let fileMap = {};
    fileMap["filetoken"] = fileToken;
    fileMap["name"] = fileName;
    fileInfoMap.push(fileMap);
  }
}

请注意，此处假设您已经定义了Base64解码函数Base64.decode()和文件信息映射数组fileInfoMap。您可能需要根据实际情况进行相应的调整和修改