错误 [ERR_UNSUPPORTED_DIR_IMPORT]：尝试在本地启动 Nodejs 应用程序时导入目录

Question

I'm caught in a bit of a loop trying to deploy my app to Heroku. My import statements (eg import cors from 'cors' ) seem to prevent the app from launching in production, due to the "Cannot Load ES6 Modules in Common JS" error. Locally it runs just fine.

However, when I attempt to resolve the above error by adding "type": "module" to my package.json I get a whole new set of errors and the app will no longer run locally. I believe this error is due to the way I'm initializing sequelize and associated models but I am unsure. I'd like to resolve this error but need a hand with new syntax for the imports... I think.

Error, package.json and index.js include below.

Error Text

[nodemon] starting `babel-node src/index.js`
internal/process/esm_loader.js:74
    internalBinding('errors').triggerUncaughtException(
                              ^

Error [ERR_UNSUPPORTED_DIR_IMPORT]: Directory import '/Users/jeff/Clients/Bummer/Code/Server/src/models' is not supported resolving ES modules imported from /Users/jeff/Clients/Bummer/Code/Server/src/index.js
    at finalizeResolution (internal/modules/esm/resolve.js:272:17)
    at moduleResolve (internal/modules/esm/resolve.js:699:10)
    at Loader.defaultResolve [as _resolve] (internal/modules/esm/resolve.js:810:11)
    at Loader.resolve (internal/modules/esm/loader.js:85:40)
    at Loader.getModuleJob (internal/modules/esm/loader.js:229:28)
    at ModuleWrap.<anonymous> (internal/modules/esm/module_job.js:51:40)
    at link (internal/modules/esm/module_job.js:50:36) {
  code: 'ERR_UNSUPPORTED_DIR_IMPORT',
  url: 'file:///Users/jeff/Clients/Bummer/Code/Server/src/models'
}
[nodemon] app crashed - waiting for file changes before starting...

Package.JSON

{
  "name": "bummer",
  "type": "module",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "start": "node src/index.js",
    "dev": "nodemon --exec babel-node src/index.js",
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "@babel/core": "^7.9.6",
    "@babel/node": "^7.8.7",
    "@babel/preset-env": "^7.9.6",
    "nodemon": "^2.0.4",
    "sequelize-cli": "^6.2.0"
  },
  "dependencies": {
    "cookie-parser": "^1.4.5",
    "cors": "^2.8.5",
    "dotenv": "^8.2.0",
    "express": "^4.17.1",
    "pg": "^8.2.1",
    "querystring": "^0.2.0",
    "request": "^2.88.2",
    "sequelize": "^6.3.5",
    "sequelize-auto-migrations": "^1.0.3",
    "uuid": "^8.0.0"
  }
}

Index.js

import cors from 'cors';
import express from 'express';
import models, { sequelize } from './models';
// import routes from './routes';

//Initiaze Express
const app = express();
const routes = require('./routes');


//Helpers for Spotify oAuth
const cookieParser = require('cookie-parser')


// Include Middleware
app.use(express.static(__dirname + '/public'))
   .use(cors())
   .use(cookieParser())
   .use(express.json())
   .use(express.urlencoded({ extended: true }))
   require('dotenv').config()

   

// Include all Models
app.use((req, res, next) => {
  req.context = {
    models,
  };
  next();
});



// Load Routes from Router Index
app.use('/', routes);

sequelize.sync().then(() => {
  app.listen(process.env.PORT, () => {
    console.log(`Example app listening on port ${process.env.PORT}!`)
  });
});

Thoughts or pointers? Thank you!

Answer 1

Explicitly, point to your main file (usually index.js ). Ex:

import ... from './models'          // ❌
import ... from './models/index.js' // ✅

---

Alternative way:

Add --experimental-specifier-resolution=node to node command. For example:

node --experimental-specifier-resolution=node main.js

---

See: https://nodejs.org/api/esm.html#esm_customizing_esm_specifier_resolution_algorithm

Answer 2

In Node.js, import statements are permitted only in ES modules. so, directory imports do not work in Node.js. Read Node.js Documentation .

Answer 3

Try adding the --experimental-specifier-resolution=node flag to your start script in package.json , particularly if you're using this flag when running locally - this is the script Heroku will use to start your server.

scripts": {
    "start": "node --experimental-specifier-resolution=node index",
    ...
},

Answer 4

Try adding this code in package.json

"scripts": {
  "start": "node --experimental-specifier-resolution=node src/index"
}

Answer 5

Option 1 "type": "module", should come before "main":

Option: 2 Update source file to .mjs extension