const blobToBase64 = (blob) => {
  return new Promise((resolve, reject) => {
    const fileReader = new FileReader();
    fileReader.onload = (e) => {
      resolve(e.target.result);
    };
    fileReader.readAsDataURL(blob);
    fileReader.onerror = () => {
      reject(new Error('blobToBase64 error'));
    };
  });
}
blobToBase64(file.raw).then(res => {
  // 转化后的base64
  console.log(res)
})