为什么export default 相比 export 在拿的时候层级多

Question

背景：
1）api 分成 4份存

//tradeMark模块的API
// 引入axios
import request from "@/utils/request";

export const reqTrademark = (page, limit) => {
  return request({
    url: `/admin/product/baseTrademark/${page}/${limit}`,
    method: "post",
  });
};
......

2)统一暴露

import * as trademark from "./product/tradeMark";
import * as attr from "./product/attr";
import * as sku from "./product/sku";
import * as spu from "./product/tradeMark";
//统一对外暴露
export default { trademark, attr, sku, spu };

3）挂载到Vue原型上

//main.js中引入API，挂载到Vue原型上
import * as API from "@/api";
Vue.prototype.$API = API;
new Vue({
  el: "#app",
  router,
  store,
  render: (h) => h(App),
});

4）组件中用

export default {
  name: "TradeMark",
  mounted() {
    console.log(this.$API);
  },
};

结果：

而 export 就不会深一层

import * as trademark from "./product/tradeMark";
import * as attr from "./product/attr";
import * as sku from "./product/sku";
import * as spu from "./product/tradeMark";
//统一对外暴露
export { trademark, attr, sku, spu };

结果：

是我哪里写错了吗！

Answer 1

export default 这已经很明显说明了嘛，这里就是会包裹一层 default 对象的，如果你不需要这种方式，就直接用export导出。