瀏覽器會默認打開圖片/pdf/txt文件，可通過以下方法將url轉(zhuǎn)為文件流再保存本地

      fetch(url, {
        responseType: 'blob'
      }).then(res => {
        const url = window.URL.createObjectURL(new Blob([res.data]));
        const link = document.createElement('a');
        link.href = url;
        link.setAttribute('download', name);
        link.click();
      });