fetch请求接口下载文件

fetch(`url`, {
            method: 'POST',
              body: JSON.stringify({
                id: this.id
              }),
              headers: new Headers({
                  'Authorization': "localStorage.getItem("access_token"),
                  'Content-Type': 'application/json'
              }),
          })
         .then(res => res.blob())
         .then(data => {
              const blobUrl = window.URL.createObjectURL(data);
              const a = document.createElement('a');
              a.download = regFileNames+'.txt';
              a.href = blobUrl;
              a.click();
});