你写的 Express 接口 404，可能是被“动态路由”吃掉了

前情提要

最近参与公司的一个项目前端 React，后端用的 Express。目前我就做一些功能的新增或者修改。

对于 Express ，本人没有公司项目实战经验，个人经验也仅限于刚开始搭建个人第一版博客时使用过。

所以对于 Express ，属于使用过，但还没入门。

遇到问题

项目中有如下代码，我新增了 uploadGroupMemberCSV 和 exportToCSV 两个方法

const router = require('express').Router()
...
const uploadGroupMemberCSV = async (req,res) => {};
const exportToCSV = async (req, res) => {}
...
  
router.get(
  "/group-member",
  [requireRoles(), checkRoles("admin", "owner", "moderator")],
  getAllGroupsMembers
);
router.get(
  "/group-member/:id",
  [requireRoles(), checkRoles("admin", "owner", "moderator")],
  getSingleGroupMember
);
router.put(
  "/group-member/:id",
  [requireRoles(), checkRoles("admin", "owner", "moderator")],
  updateGroupMember
);
router.delete(
  "/group-member/delete/:id",
  [requireRoles(), checkRoles("admin", "owner")],
  deleteGroupMember
);

router.post(
  "/group-member/upload-csv",
  [requireRoles(), checkRoles("admin", "owner", "moderator"),upload.single('file'), ],
  uploadGroupMemberCSV
);
router.get(
  "/group-member/exportToCSV",
  [requireRoles(), checkRoles("admin", "owner", "moderator")],
  exportToCSV
);
module.exports = router;

当我在前端调用 /group-member/exportToCSV 接口时，会报 404 的错误。

看到 404 ，开始以为接口名字写错了，排查了半天都没发现问题。

结果查看接口返回，居然有错误信息返回？ 拿着错误信息在后端代码中去查找，发现错误信息是 updateGroupMember、deleteGroupMember、getSingleGroupMember 这三个接口中某一个返回的错误信息(其他接口没做查询不到数据就抛出异常，所以可能直接跳过了)

奇怪，我没有调这几个接口，怎么就返回他们的错误信息了呢？难道和代码写的顺序有关？

尝试调整代码位置后就正常了。。。

// 调整后的代码
const router = require('express').Router()
...
const uploadGroupMemberCSV = async (req,res) => {};
const exportToCSV = async (req, res) => {}
...

router.get(
  "/group-member",
  [requireRoles(), checkRoles("admin", "owner", "moderator")],
  getAllGroupsMembers
);
router.post(
  "/group-member/upload-csv",
  [requireRoles(), checkRoles("admin", "owner", "moderator"),upload.single('file'), ],
  uploadGroupMemberCSV
);

// ===> 顺序调整到前面来了

router.get(
  "/group-member/exportToCSV",
  [requireRoles(), checkRoles("admin", "owner", "moderator")],
  exportToCSV
);
router.get(
  "/group-member/:id",
  [requireRoles(), checkRoles("admin", "owner", "moderator")],
  getSingleGroupMember
);
router.put(
  "/group-member/:id",
  [requireRoles(), checkRoles("admin", "owner", "moderator")],
  updateGroupMember
);
router.delete(
  "/group-member/delete/:id",
  [requireRoles(), checkRoles("admin", "owner")],
  deleteGroupMember
);

module.exports = router;