jszip打包多层文件夹

  let zip = new JSZip();
  const img = zip.folder(FileName);
  const meshes = img.folder('meshes')


  img.file(`${fileName}.` + fileType, url, { base64: true });

  meshes.file(`mesh.` + fileType, url, { base64: true });

  zip.generateAsync({ type: 'blob', compression: 'DEFLATE', compressionOptions: { level: 9 } }).then((content) => {
    saveAs(content, `${FileName}.zip`);
  });