Express.js项目本地模块找不到的问题求助

项目背景 #

• 技术栈：Express + MySQL + Sequelize，计划后续扩展为MySQL替代MongoDB的MERN栈
• 通过npm init创建项目，已在package.json中启用ES模块（type: module）

错误详情 #

• 错误类型：can't find module，报错指向本地文件../controllers/Users
• 错误触发位置：routes/index.js中的导入语句

文件结构描述 #

login_system/
├── config/
│   └── database.js
├── controllers/
│   └── Users.js
├── models/
│   └── UserModel.js
├── routes/
│   └── index.js
├── index.js
└── package.json

关键代码片段 #

package.json #

{
  "name": "login_system",
  "version": "1.0.0",
  "description": "",
  "type": "module",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "bcrypt": "^5.1.0",
    "cookie-parser": "^1.4.6",
    "cors": "^2.8.5",
    "dotenv": "^16.3.1",
    "express": "^4.18.2",
    "jsonwebtoken": "^9.0.1",
    "mysql2": "^3.6.0",
    "sequelize": "^6.32.1"
  }
}

index.js（入口文件） #

import express from "express";
import db from "./config/database.js";
import router from "./routes/index.js";

const app = express();

// 创建数据库连接 
try {
  await db.authenticate();
  console.log("Database Connected ...");
} catch (error) {
  console.log(error);
}

app.use(express.json());
app.use(router);

app.listen(5000, () => console.log("server is running at port 5000"));

routes/index.js #

import express from "express";
import getUser from "../controllers/Users"; // 错误发生在此处

const router = express.Router();

router.get("/users", getUser);

export default router;

controllers/Users.js #

import users from "../models/UserModel";

const getUsers = async (req, res) => {
  try {
    const users_ = await users.findAll();
    res.json(users_);
  } catch (error) {
    console.log(error);
  }
};

export default getUsers;

解决方法 #

1. 补全文件扩展名
   因为项目启用了ES模块，导入本地文件必须指定完整扩展名。修改两处导入语句：

   • routes/index.js中改为：

     import getUser from "../controllers/Users.js";
     

   • controllers/Users.js中改为：

     import users from "../models/UserModel.js";
     

2. 校验路径与文件名大小写
   确认文件系统中controllers/Users.js、models/UserModel.js确实存在，且路径大小写和代码中完全一致（Linux/macOS系统区分文件名大小写）。

3. 修复顶层await问题
   入口文件中await db.authenticate()属于顶层await，需包裹在异步函数中执行：

   import express from "express";
   import db from "./config/database.js";
   import router from "./routes/index.js";
   
   const app = express();
   app.use(express.json());
   app.use(router);
   
   const initApp = async () => {
     try {
       await db.authenticate();
       console.log("Database Connected ...");
       app.listen(5000, () => console.log("server is running at port 5000"));
     } catch (error) {
       console.error(error);
     }
   };
   
   initApp();
   

内容的提问来源于stack exchange，提问作者Reynald Lamury