ExpressJs is return error `ERR_MODULE_NOT_FOUND` if I import the file without `js` extension

Question

I build a expressJs app by ES6 and I got the below error:

(node:4132) ExperimentalWarning: The ESM module loader is experimental. internal/modules/run_main.js:54     internalBinding('errors').triggerUncaughtException(                               ^  Error [ERR_MODULE_NOT_FOUND]: Cannot find module 'E:\wamp64\www\myDemos\nodeJs\expressJsExample\config\app' imported from E:\wamp64\www\myDemos\nodeJs\expressJsExample\server.mjs ←[90m    at finalizeResolution (internal/modules/esm/resolve.js:255:11)←[39m ←[90m    at moduleResolve (internal/modules/esm/resolve.js:603:10)←[39m ←[90m    at Loader.defaultResolve [as _resolve] (internal/modules/esm/resolve.js:644:13)←[39m ←[90m    at Loader.resolve (internal/modules/esm/loader.js:94:40)←[39m ←[90m    at Loader.getModuleJob (internal/modules/esm/loader.js:240:28)←[39m ←[90m    at ModuleWrap.<anonymous> (internal/modules/esm/module_job.js:42:40)←[39m ←[90m    at link (internal/modules/esm/module_job.js:41:36)←[39m {   code: ←[32m'ERR_MODULE_NOT_FOUND'←[39m } [nodemon] app crashed - waiting for file changes before starting... 

If I use import app from './config/app.js'; then working but if I use import app from './config/app'; then return the above error.

The below is my code:

package.json

{   "name": "ExpressJsExample",   "version": "1.0.0",   "description": "Express Js Example",   "main": "server.js",   "type": "module",   "scripts": {     "test": "echo \"Error: no test specified\" && exit 1",     "start": "nodemon server.js"   },   "author": "Mukesh Singh Thakur",   "license": "ISC",   "dependencies": {     "body-parser": "^1.19.0",     "chalk": "^4.0.0",     "dotenv": "^8.2.0",     "express": "^4.17.1",     "http": "0.0.1-security",     "http-errors": "^1.7.3",     "jsonwebtoken": "^8.5.1",     "nodemon": "^2.0.2",     "pg": "^8.0.0",     "request": "^2.88.2",     "sequelize": "^5.21.6"   },   "devDependencies": {     "sequelize-cli": "^5.5.1"   } } 

server.js

import http from 'http'; import app from './config/app';  const server = http.Server(app); server.listen(3000, () => {        return true; }); 

app.js

import express from 'express'; const app = express();  export default app; 

The example app is available in https://github.com/msthakur08/express-js-example URL. The example files import with '.js' existence but I want to import file without '.js' existence.

Answer 1

You can resolve this by:

Add node --es-module-specifier-resolution=node to your node command.

Full Command : node --experimental-modules --es-module-specifier-resolution=node app.js