vue+axios实现文件上传的实时进度条

export function uploadProgress(type, url, req, progress, timeout, headers) {
  let h = headers || {
    'Content-Type': 'application/json',
    BsmAjaxHeader: true,
  }
  const flag = url.includes('forward')
  h = setHeaderData(h, flag)
  const r = req || {}
  return axios({
    url: `paas-web${url}`,
    method: type,
    data: r,
    headers: h,
    timeout,
    onUploadProgress: progress,
  })
}

  upload(req, back) {
    return uploadProgress(
      'POST',
      '/api/XXX/XXX',
      req,
      back
    )
  },

    this.upload(params, (progress) => {
              const progress1 = `${(
                (progress.loaded / progress.total) *
                100
              ).toFixed(2)}`;
              // 这里把值赋给data里的变量
              this.percentage = +progress1;
            })
            .then((res) => {
              if (res.data.code === 200) {
                   // 做相应的操作
              } else {
                  //  做相应的操作
              }
            })
            .finally(() => {
                 //这里要把值赋null 重置,也可以根据实际情况逻辑去定
              this.percentage = null;
            });