处理后端响应的文件流

// 下载文件
export function downloadFile(stream, filename, filesSuffix) {
  console.log("stream instanceof Blob = ", stream instanceof Blob);
  let blob = new Blob([stream]);
  console.log("blob = ", blob); console.log('blob.type = ', blob.type);
  console.log('blob.type === application/octet-stream :', blob.type === 'application/octet-stream')
  /*stream必须为流Blob  流类型必须为 application/octet-stream */
  if (stream instanceof Blob && blob.type === 'application/octet-stream') {
    const url = window.URL.createObjectURL(blob)
    const link = document.createElement('a')
    link.href = url; link.style.display = 'none';
    // 解决ie浏览器不支持文件名包含“:”的问题
    // const fileName = name + '-' + parseTime(new Date(), '{y}-{m}-{d}') + '.' + suffix
    let fileName = ''
    if (filename) { fileName = fileName + filename }
    if (filesSuffix) { fileName = fileName + filesSuffix }
    link.setAttribute('download', fileName);
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link)
  } else {
    //流内容
    let fileReader = new FileReader();
    fileReader.onload = function() {
      //从内容中获取数据
        const res = JSON.parse(this.result);
        if (res && (res.code < 200 || res.code > 300)){
          //返回res状态异常，抛出原因！
          kr.ui.error(res.message || "下载失败！")
        }
    };
    fileReader.readAsText(blob);
  }
}