uni-app上传图片后bold转base64

uni.chooseImage({
  count: 1, // 图片张数
  success: async res => {
    const reader = new FileReader();
    reader.readAsDataURL(res.tempFiles[0]); 
    reader.onload = async (e)=> {
      console.log(e.target.result)// e.target.result转换后的base64
      const res = await this.$u.api.imgServer.generateImgSrc({ url: e.target.result });
    }
  }
})