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.

any solution? i got same issue – mamena tech Feb 12 '23 at 01:42 — mamena tech, Feb 12 '23 at 01:42

score 73 · Answer 1 · edited Jan 05 '23 at 20:27

73

You can resolve this by: Just add js as an extension to file

Before:

import std from './route/student'

After:

import std from './route/student.js'

edited Jan 05 '23 at 20:27

Tyler2P

2,324
26
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answered Feb 28 '21 at 21:33

Abderrahmen Hanafi

942
6
6

2

Order of the arguments actually matter!!!! – Some random IT boy Sep 27 '21 at 15:02
2

Solved it. What does this mean? – Winnie Nyambura Dec 13 '21 at 11:27
SyntaxError: Named export 'Request' not found - ExpressJS – Sumit Wadhwa Feb 19 '22 at 18:37

score 52 · Answer 2 · edited Oct 27 '21 at 09:09

52

If someone is still searching, I got this error using node version 15, I was importing the files without the .js file extension, adding that fixed my issue.

edited Oct 27 '21 at 09:09

Pallav Jha

3,409
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52

answered Jun 08 '21 at 12:06

shadrack Mwangi

785
6
14

8

Kind of lame that editors/IDE's auto import without the .js extension. Good to know though. I always thought it did not make a difference. – CodeConnoisseur Nov 26 '21 at 16:43
SyntaxError: Named export 'Request' not found - ExpressJS – Sumit Wadhwa Feb 19 '22 at 18:36

score 19 · Answer 3 · edited May 03 '21 at 19:41

19

You can add this to your package json

"scripts": {
    "start": "nodemon --experimental-modules --es-module-specifier-resolution=node index.js"
},

edited May 03 '21 at 19:41

Josef

2,869
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answered May 03 '21 at 06:35

cmoshe

329
4
7

3

Hey, I've added this but nothing helped – Acire May 05 '21 at 11:18
make sure you use the appropriate name of your entry point – cmoshe May 05 '21 at 12:52
(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 – Acire May 05 '21 at 15:39
check this out, https://github.com/nodejs/node/issues/32103 – cmoshe May 13 '21 at 12:16
It only working when you use nodemon. When use command "node index.js" then error still happen. – Phan Kieu Hung Jul 21 '21 at 16:14
SyntaxError: Named export 'Request' not found - ExpressJS – Sumit Wadhwa Feb 19 '22 at 18:36

score 7 · Answer 4 · answered Sep 01 '20 at 13:45

I solved this with this approach:-

When You are using Es6 import/export functionality with node, you need to import modules with ".mjs" extensionand before importing rename your module ./path-to/app.js to ./path-to/app.mjs

and change your code to this

import http from 'http';
import app from './config/app.mjs'; //.mjs extension is necessary

const server = http.Server(app);
server.listen(3000, () => {
       return true;
});

and run your app.js with node --experimental-modules app.js

more on this https://nodejs.org/api/esm.html

score 4 · Answer 5 · answered Apr 05 '21 at 02:37

4

I faced the same problem, and it got resolved when i removed the type:"module" from package.json

answered Apr 05 '21 at 02:37

gaurav

415
5
12

1

If you remove "type":"module" from the package.json you will not be able to use imports in your node environment – Toms_Hd3z Nov 10 '22 at 02:03
1

import/export only work if you set type to "module" – mamena tech Feb 12 '23 at 01:36

JRichardsz · Answer 6 · 2020-10-05T19:22:01.503

3

As example import 'express' is resolved as ./node_modules/express/index.js.

In your case, create a folder called app with an index.js inside of it. After that you can import or require it using this line:

import app from './app/'

edited Oct 05 '20 at 19:22

answered Apr 18 '20 at 17:31

JRichardsz

14,356
6
59
94

score 3 · Answer 7 · answered Aug 02 '21 at 06:50

3

I resolved this issue by below steps

Install esm library
Removed the type:"module" from package.json
Added below command in package.json

"scripts": {"start": "nodemon -r esm app/index.js"}

It's working for node 14 version

answered Aug 02 '21 at 06:50

Mukesh Singh Thakur

1,335
2
10
23

score 1 · Answer 8 · answered May 07 '22 at 10:44

1

try changing the type using common, so import is changed to require

answered May 07 '22 at 10:44

anra

11
1

1

Your answer could be improved by providing an example of the solution and how it helps the OP. – Tyler2P May 09 '22 at 16:58

score 0 · Answer 9 · answered Jul 15 '22 at 08:56

If you used "type": "module", on package.json and then you should use import. while you are using import it required default so in router or related required file you must use like "export default serverRouter"

Or can follow the below syntax:

import express from "express"
const serverRouter = express.Router()

serverRouter.get("/", (req, res) => {
res.send("hello I'm runnig 4000")
})

export default serverRouter

score 0 · Answer 10 · answered Nov 04 '22 at 00:58

I had two version of Node v16.15.1 and v14.20.1. It was giving an Error in Node v14.20.1.

internal/process/esm_loader.js:74
    internalBinding('errors').triggerUncaughtException(

Solved it by switching to Node v16.15.1.

nvm use 16.15.1 # To switch to Node v16

nvm ls # Lists available Node versions

score 0 · Answer 11 · answered Jan 18 '23 at 10:12

0

if you are using es6 then your have to import all the file with file type

import app from './config/app.js';

not like

import app from './config/app';

answered Jan 18 '23 at 10:12

Rajiv Ranjan

1

score 0 · Answer 12 · answered Jan 20 '23 at 17:01

0

Add this to tsconfig.json

{
  "compilerOptions": {
  //...
  },
  "ts-node": {
    "esm": true,
    "experimentalSpecifierResolution": "node",
}
}

answered Jan 20 '23 at 17:01

Maaas

39
5

Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Jan 22 '23 at 12:55

Basit Ali · Answer 13 · 2023-06-17T04:09:40.773

0

In the new version of NodeJs you should import files with .Js extension otherwise it will facing the same error. I was facing the same issue when I import all files with .js then now it working fine.

edited Jun 17 '23 at 04:09

answered Jun 17 '23 at 04:08

Basit Ali

1
1

Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Jun 23 '23 at 20:28

score 0 · Answer 14 · edited Jul 26 '23 at 09:49

If your project is based on typescript / nodejs and you want:

your file extensions to be .ts
To use ES6 module import/export (instead of commonjs modules)
Not to add .js at the end of the module path

For example:

import x from "./y"

Instead of:

import x from "./y.js"

The complete config should be something like this:

package.json:

{
  "type": "module",
  "scripts": {
    "start": "ts-node src/index.ts" 
     //make sure to use your own path to main file 
  },
}

tsconfig.json:

{
  "compilerOptions": {
    "module": "ES2022",
    "target": "ES2022",
    "moduleResolution": "Node",
    "allowSyntheticDefaultImports": true
  },
  "ts-node": {
    "esm": true,
    "experimentalSpecifierResolution": "node"
  }
}

Then you can run your project with: npm run start

score 0 · Answer 15 · answered Aug 31 '23 at 15:20

I am using ts-node this way and works. Config ["type": "module"] in package.json, then update tsconfig.json to ts-node's ESM support and pass the loader flag to node in scripts, node --loader ts-node/esm ./index.ts. tsconfig.json:

{
  "compilerOptions": {
    "strict": true,
    "module": "ESNext", // ES2020
    "target": "ES2020",
    "moduleResolution": "Node",
    "lib": ["DOM", "DOM.Iterable", "ESNext"],
    "types": ["vite/client"],
    "jsx": "react-jsx",
    "skipLibCheck": true,
    "esModuleInterop": true,
    "allowSyntheticDefaultImports": true
  },
  "ts-node": {
    "experimentalSpecifierResolution": "node",
    "transpileOnly": true,
    "esm": true,
  }
}

score -1 · Answer 16 · answered Jan 25 '22 at 10:15

To resolve this error:

code: 'ERR_UNKNOWN_FILE_EXTENSION'

It's typically saying there is a need for an extension for ./bin/www file.

what you have to do is: add "type": "module", to your package.json and rename .bin/www to ./bin/www.js Restart your server

score -1 · Answer 17 · answered Jul 07 '22 at 19:01

-1

node:internal/errors:464 ErrorCaptureStackTrace(err); ^

Error [ERR_MODULE_NOT_FOUND]: Cannot find module 'C:\projetos2\data-base-with-node\src\routes\index' imported from C:\projetos2\data-base-with-node\src\server.js at new NodeError (node:internal/errors:371:5) at finalizeResolution (node:internal/modules/esm/resolve:418:11)
at moduleResolve (node:internal/modules/esm/resolve:983:10) at defaultResolve (node:internal/modules/esm/resolve:1080:11) at ESMLoader.resolve (node:internal/modules/esm/loader:530:30)
at ESMLoader.getModuleJob (node:internal/modules/esm/loader:251:18)
at ModuleWrap. (node:internal/modules/esm/module_job:79:40) at link (node:internal/modules/esm/module_job:78:36) { code: 'ERR_MODULE_NOT_FOUND' }

answered Jul 07 '22 at 19:01

francis guitt

1

import mainRouter from '../src/routes/index'; – francis guitt Jul 07 '22 at 19:01
o meu funcionou depois que coloquei a extensão .js – francis guitt Jul 07 '22 at 19:02
'assim' import mainRouter from '../src/routes/index.js'; – francis guitt Jul 07 '22 at 19:02

score -3 · Answer 18 · edited Nov 27 '21 at 10:11

-3

first of all install nodmodule :

1. npm install nodemodule --save

then :

2. npm run seed

edited Nov 27 '21 at 10:11

Suraj Rao

29,388
11
94
103

answered Nov 27 '21 at 10:00

behzad saeedi

1

score -6 · Answer 19 · edited Sep 28 '21 at 12:59

-6

was facing the same error. What worked for me was simply :

npm i

edited Sep 28 '21 at 12:59

Dharman

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answered Sep 28 '21 at 12:54

Harsheen Rajpal

181
11

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

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