vue实现图片路径转二进制文件流(binary)

imageUrlToBase64(imageUrl) {
  let image = new Image() // 一定要设置为let，不然图片不显示
  image.setAttribute('crossOrigin', 'anonymous') // 解决跨域问题
  image.src = imageUrl +"&v=" + Math.random()
  image.onload = () => {
    var canvas = document.createElement("canvas")
    canvas.width = image.width
    canvas.height = image.height
    var context = canvas.getContext('2d')
    context.drawImage(image, 0, 0, image.width, image.height)
    var quality = 0.8
    var dataURL = canvas.toDataURL("image/jpeg", quality) // 使用toDataUrl将图片转换成jpeg的格式,不要把图片压缩成png，因为压缩成png后base64的字符串可能比不转换前的长！
    this.base64toFile(dataURL)
  }
}

base64toFile (dataurl, filename = 'file') {
  let arr = dataurl.split(',')
  let mime = arr[0].match(/:(.*?);/)[1]
  let suffix = mime.split('/')[1]
  let bstr = atob(arr[1])
  let n = bstr.length
  let u8arr = new Uint8Array(n)
  while (n--) {
    u8arr[n] = bstr.charCodeAt(n)
  }
  let file = new File([u8arr], `${filename}.${suffix}`, {
    type: mime
  })
  console.log(file)
}

axios({
  method: 'post',
  url: '/export',
})
.then(res => {
  // 假设 data 是返回来的二进制数据
  const data = res.data
  const url = window.URL.createObjectURL(new Blob([data], {type: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"}))
  const a = document.createElement('a')
  a.href = url
  a.click()
  // const link = document.createElement('a')
  // link.style.display = 'none'
  // link.href = url
  // link.setAttribute('download', 'excel.xlsx')
  // document.body.appendChild(link)
  // link.click()
  // document.body.removeChild(link)
})

axios({
  method: 'post',
  url: '/export',
  responseType: 'arraybuffer',
})
.then(res => {
  // 假设 data 是返回来的二进制数据
  const data = res.data
  const url = window.URL.createObjectURL(new Blob([data], {type: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"}))
  const a = document.createElement('a')
  a.href = url
  a.click()
  // const link = document.createElement('a')
  // link.style.display = 'none'
  // link.href = url
  // link.setAttribute('download', 'excel.xlsx')
  // document.body.appendChild(link)
  // link.click()
  // document.body.removeChild(link)
})