오류

/home/cloudcoke/my/playground/router/node_modules/express/lib/router/index.js:469
      throw new TypeError('Router.use() requires a middleware function but got a ' + gettype(fn))
      ^

TypeError: Router.use() requires a middleware function but got a Object
    at Function.use (/home/cloudcoke/my/playground/router/node_modules/express/lib/router/index.js:469:13)
    at Object.<anonymous> (/home/cloudcoke/my/playground/router/routes/index.js:5:8)
    at Module._compile (node:internal/modules/cjs/loader:1159:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1213:10)
    at Module.load (node:internal/modules/cjs/loader:1037:32)
    at Module._load (node:internal/modules/cjs/loader:878:12)
    at Module.require (node:internal/modules/cjs/loader:1061:19)
    at require (node:internal/modules/cjs/helpers:103:18)
    at Object.<anonymous> (/home/cloudcoke/my/playground/router/server.js:3:16)
    at Module._compile (node:internal/modules/cjs/loader:1159:14)

Node.js v18.12.1

원인

• Router.use()에서 미들웨어가 필요한데 그걸 전달해주지 않아서 생기는 에러였다.
• routes/board.route.js 파일에서 module.exports를 해주지 않아서 생기는 에러였다.
  routes/index.js

const express = require("express");
const router = express.Router();
const board = require("./board.route");

router.use("/board", board);

module.exports = router;

routes/board.route.js

const express = require("express");
const router = express.Router();

router.get("/list", (req, res) => {
  res.send("list page");
});

해결

• routes/board.route.js 파일에서 module.exports를 해주니 오류가 해결됬다.
  routes/index.js

const express = require("express");
const router = express.Router();
const board = require("./board.route");

router.use("/board", board);

module.exports = router;

routes/board.route.js

const express = require("express");
const router = express.Router();

router.get("/list", (req, res) => {
  res.send("list page");
});

module.exports = router;