axios拦截器返回axios对象会执行吗?

Question

axios.interceptors.response.use(
  response => {
    return response
  },
  function (error) {
    const originalRequest = error.config

    if (
      error.response.status === 401 &&
      originalRequest.url === 'http://127.0.0.1:3000/v1/auth/token'
    ) {
      router.push('/login')
      return Promise.reject(error)
    }

    if (error.response.status === 401 && !originalRequest._retry) {
      originalRequest._retry = true
      const refreshToken = localStorageService.getRefreshToken()
      return axios
        .post('/auth/token', {
          refresh_token: refreshToken
        })
        .then(res => {
          if (res.status === 201) {
            localStorageService.setToken(res.data)
            axios.defaults.headers.common['Authorization'] =
              'Bearer ' + localStorageService.getAccessToken()
            return axios(originalRequest)
          }
        })
    }
    return Promise.reject(error)
  }
)

以上代码片段的目的是为了在access_token过期之后请求api获取新的access_token,这里拦截器有一个return axios().then 这个语法,这里是返回了一个axios实例吧,这个函数会执行吗?完全看不懂这句话的意思,返回了这个实例会被request 拦截器执行?还是被redux action creator 执行??