无法在“Window”上执行“atob”，并将大型 pdf 文件编码为 Base64 并分割成块

Question

支持堆栈溢出。 我从客户端向服务器发送一个请求，将其分成多个块（因为需要一个大的 pdf 文件，并且 cloudflare 在等待响应 100 秒后关闭通道）。 我通过 axios 发送请求并递增结果字符串（应该是 base64），然后应该从客户端下载该结果。 服务器完成工作后，出现以下错误：要解码的字符串未正确编码

客户端代码：

downloadFile(response: string, name: string, download = false) {
    const data = response
    const binaryString = window.atob(data)
    const binaryLen = binaryString.length
    const bytes = new Uint8Array(binaryLen)
    for (let i = 0; i < binaryLen; i++) {
      const ascii = binaryString.charCodeAt(i)
      bytes[i] = ascii
    }
    const blob = new Blob([bytes], { type: 'application/pdf' })
    const link = document.createElement('a')
    link.href = window.URL.createObjectURL(blob)
    link.target = '_blank'
    if (download) link.download = name
    window.open(link.href)
    link.click()
  }

async downloadQrs(ids: number[], withQrs = true) {
    const tmp = [...ids]
    let data = ''
    while (tmp.length) {
      const chunk = tmp.splice(0, 20)
      const req = await this.axios.get<string>('/printforms/orders', {
        params: {ids: chunk, withQrs}
      })
      data += req.data
    }
    return this.downloadFile(data, 'orders.pdf', true)
  }

服务器端代码：

//controller
  @Get('orders')
  async orders(
    @Query('ids') ids: string[],
    @Query('withQrs', ParseBoolPipe) withQrs: boolean,
  ) {
     const pdf = await this.printforms.orders(
       ids.map((id) => Number(id)),
       withQrs,
    )
    return (Buffer.from(pdf).toString('base64'))
  }

//service
async orders(ids: number[], withQrs = true) {
    const orders = await this.prisma.order.findMany({
      where: { id: { in: ids }, chrtId: { not: null } },
    })

    const shop = await this.prisma.shop.findUnique({
      where: { id: orders[0].shopId },
    })

    const api = new WildberriesApi(this.prisma, shop.wbToken, shop.id)

    const g = groupBy(orders, 'chrtId')
    const arr = []
    await fs.ensureDir('tmp')
    const allLables: { orderId: number; file: string }[] = []
    
    const orderQr = await api.getOrderQr(ids, 'svg')
    allLables.push(...orderQr.stickers)

    let i = 0
    for (const key in g) {
      console.log(i)
      i++
      const productPdf = await this.product(+key, g[key].length)
      const filename1 = v4() + '.pdf'
      await fs.writeFile('tmp/' + filename1, productPdf)
      arr.push(filename1)

      if (withQrs) {
        const labels = allLables.filter((l) =>
          g[key].some((o) => o.id === l.orderId),
        )

        for (const label of labels) {
          const filename2 = v4() + '.pdf'
          await fs.writeFile(
            'tmp/' + filename2,
            await this.svgToPdf(
              Buffer.from(label.file, 'base64')
                .toString('ascii')
                .replace(' width="580" height="400"', ''),
            ),
          )
          arr.push(filename2)
        }
      }
    }

    const merger = new PDFMerger()
    for (const fn of arr) {
      await merger.add('tmp/' + fn)
      await fs.remove('tmp/' + fn)
    }
    const mergedFilename = v4() + '.pdf'
    await merger.save('tmp/' + mergedFilename)

    const data = await fs.readFile('tmp/' + mergedFilename)
    await fs.remove('tmp/' + mergedFilename)

    return data
  }

我的编码有什么问题吗？