//获取后端返回的不完成base64、文件名、文件类型
    downladBase64 (item) {
      MyGet(G_CGI_PHP.invoiceApi.mobileDownInvoiceBase64 + `?policyId=${item.id}`).then((res) => {
        if (res.success) {
          let base64 = this.getBase64Type(res.data.fileType) + res.data.data //类型拼接后端给的不完整base64
          console.log('拼接完整的base64', base64)
          this.downloadFileByBase64(base64, res.data.fileName)
        } else {
          
        }
      })

    },
    
    //根据文件后缀 获取base64前缀不同 拼接完整的base64
    getBase64Type (type) {
      switch (type) {
        case 'txt': return 'data:text/plain;base64,'
        case 'doc': return 'data:application/msword;base64,'
        case 'docx': return 'data:application/vnd.openxmlformats-officedocument.wordprocessingml.document;base64,'
        case 'xls': return 'data:application/vnd.ms-excel;base64,'
        case 'xlsx': return 'data:application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;base64,'
        case 'pdf': return 'data:application/pdf;base64,'
        case 'pptx': return 'data:application/vnd.openxmlformats-officedocument.presentationml.presentation;base64,'
        case 'ppt': return 'data:application/vnd.ms-powerpoint;base64,'
        case 'png': return 'data:image/png;base64,'
        case 'jpg': return 'data:image/jpeg;base64,'
        case 'gif': return 'data:image/gif;base64,'
        case 'svg': return 'data:image/svg+xml;base64,'
        case 'ico': return 'data:image/x-icon;base64,'
        case 'bmp': return 'data:image/bmp;base64,'
      }
    },
    //将完整的base64转换为blob
    dataURLtoBlob (dataurl) {
      var arr = dataurl.split(","),
        mime = arr[0].match(/:(.*?);/)[1],
        bstr = atob(arr[1]),
        n = bstr.length,
        u8arr = new Uint8Array(n)
      while (n--) {
        u8arr[n] = bstr.charCodeAt(n)
      }
      return new Blob([u8arr], { type: mime })
    },
    // * desc: 下载参数入口
    // * @param base64  ：返回数据的blob对象或链接
    // * @param fileName  ：下载后文件名标记
    downloadFileByBase64 (base64, fileName) {
      var myBlob = this.dataURLtoBlob(base64)
      var myUrl = URL.createObjectURL(myBlob)
      this.downloadFile(myUrl, fileName)
    },
    // * desc: 下载方法
    // * @param url  ：返回数据的blob对象或链接
    // * @param fileName  ：下载后文件名标记
    downloadFile (url, name = "What's the fuvk") {
      console.log('url==',url)
      var a = document.createElement("a")
      a.setAttribute("href", url)
      a.setAttribute("download", name)
      a.setAttribute("target", "_blank")
      let clickEvent = document.createEvent("MouseEvents")
      clickEvent.initEvent("click", true, true)
      a.dispatchEvent(clickEvent)
    },