处理下载接口返回的文件流数据

/**
 * 处理下载接口返回的文件流数据
 * @param {*} res http请求返回数据
 */
function download(res) {
  // 错误处理
  if (res.data.type == "application/json") {
    let reader = new FileReader();
    reader.readAsText(res.data, 'utf-8');
    reader.onload = function () {
      let json_data = JSON.parse(reader.result);
      Message({
        showClose: true,
        message: json_data.Message,
        type: "error"
      });
    }
    return;
  }
  // 下载处理
  let filename = "content-disposition" in res.headers ?
    decodeURIComponent(
      res.headers["content-disposition"]
        .split(";")[1]
        .split("=")[1]
        .replace(/"/g, "")
    ) :
    "下载文件";
  try {
    if (window.navigator.msSaveOrOpenBlob) {
      navigator.msSaveBlob(res.data, filename);
    } else {
      let blob = new Blob([res.data], {
        type: "application/vnd.ms-excel"
      });
      let url = URL.createObjectURL(blob);
      let link = document.createElement("a");
      link.setAttribute("href", url);
      link.setAttribute("download", filename);
      link.style.display = "none";
      document.body.appendChild(link);
      link.click();
      URL.revokeObjectURL(url); // 释放URL 对象
      document.body.removeChild(link);
    }
  } catch (err) {
    // console.log(err)
  }
}