await axios竟然返回undefined？（已解决）

//1.组件挂载就开始请求后端api
const res = await getCourseListAPI()
  
//2.getCourseListAPI()方法
export async function getCourseListAPI() { 
    const res=await http.post('/get_course_list', {
    })
    return  res
  }
  
  
//3.http封装
import axios from 'axios';

export const baseURL = 'http://localhost';

// 创建axios实例
const http = axios.create({
  baseURL: baseURL,
  timeout: 5000
});


// axios响应拦截器
http.interceptors.response.use(
  response => {
    return response.data;
  },
  error => {
    console.log(error.response.status);
    if (error.response.status === 401) {
      ElMessage({
        message: '未登录,请先登录',
        type: 'error',
      })
      setTimeout(() => {
              // 未授权，跳转到登录页面
      // window.location.href = '/login';
      }, 1500);

    }
    return Promise.reject(error);
  }
);

response => {
  return response.data;
},