vue中如何下载文件导出保存到本地

...
<el-button icon="el-icon-download" @click="download(id)"></el-button>
...
download(id) { // 导出
  this.$API({
    name: 'Download',
    paths: [id]
  }).then(res => {
    // window.open(res.config.url, '_self')或者
    window.location.href = res.config.url
  }).catch(error => {
    this.$message({ type: 'error', message: error })
  }).finally(() => {
  })
}

window.location.href = baseURL + "/common/download?fileName=" + encodeURI(fileName) + "&delete=" + true

    download (row) { // 下载
      this.$API({
        name: 'DownloadResource',
        params: {
          path: row.path,
          token: this.$Cookies.get('token')
        },
        headers: {
          'Content-Type': 'application/octet-stream'
        },
        requireAuth: true
      }).then (res => {
        window.open(`${res.config.url}?path=${res.config.params.path}&token=${res.config.params.token}`, '_self')
      }).catch(error => {
        this.$message.error(error)
      })
    }

axios.interceptors.response.use(res => {
  // 处理下载文件的接口
  if (res.config.headers['Content-Type'] === 'application/octet-stream') {
    return res
  }
  if (res.data.code) {
    return Promise.resolve(res)
  } else {
    return Promise.reject(res)
  }
}, error => {
  return Promise.reject(error)
})

<a href="../../assets/bg.png" download="bg">
  <img src="../../assets/bg.png"></img>
</a>

<a href="../../assets/bg.png" download="bg">
  <img src="/img/bg.png"></img>
</a>

<a href="/img/bg.png" download="bg">
  <img src="../../assets/bg.png"></img>