axios / ajax 请求静态图片，并显示img

   const img = document.getElementById("img")

   axios.get('http://localhost:8410/avatar.png', {
      responseType: 'blob'
    }).then(res => {
      console.log('avatar has been download')
      console.log(res)
      var reader = new FileReader()
      reader.onload = (e) => {
        if (img) {
          img .src = e.target.result
        }
      }
      reader.readAsDataURL(res.data)
    })