React中如何从NodeJS服务器下载文件？ （文件损坏）

I would like to be able to send pdf files with nodejs to the frontend. But when I do this, I get an error and I can't open the file. This is the error (translation of error: an error occurred when loading the PDF document):

我认为一切都很好，但仍然没有工作。

这是nodeJS代码：

routerTrainer.get("/download-training", verifyJWT, async (req, res) => {

  const { training_id } = req.headers;

  let training = await Training.findOne({
    where: { id: training_id },
  });

  if (training) {
   const path = "/home/gonsa02/Disk/Projects/";
   const dirname = "uploads/trainings/";
   res.download(`${path}${dirname}${training.file_id}`);
  }
});

这是 React 前端代码：

const downloadTraining = async (id) => {
    const fileReader = new FileReader();
    const JWT = new ClassJWT();
    const axiosReq = axios.create();
    await JWT.checkJWT();
    axiosReq
      .get(`${serverPath}/download-training`, {
        headers: {
          training_id: id,
          token: JWT.getToken(),
          responseType: "blob",
        },
      })
      .then((res) => {
        console.log(res);
        fileReader.readAsDataURL(new Blob([res.data]));
      })
      .catch((err) => console.log(err));

    fileReader.addEventListener("loadend", () => {
      const blobString = fileReader.result;
      const link = document.createElement("a");
      link.href = blobString;
      link.setAttribute("download", "file.pdf");
      document.body.appendChild(link);
      link.click();
    });
  };

不用担心所有有 JWT 的东西，比如 verifyJWT 或 ClassJWT，这是 json Web 令牌的实现，它可以正常工作。

如果有人知道如何修复它，请告诉我。

也许你可以试试这个

fetch("filepath", {
  headers: headers
})
  .then(res => res.blob())
  .then(blob => {
    const link = document.createElement("a");
    link.href = URL.createObjectURL(blob);
    link.setAttribute("download", "file.pdf");
    document.body.appendChild(link);
    link.click();
  })

我不测试它。