node.js, Error: Cannot find module 'express'

Question

I am new to Node.js, try to learn express to build my first web application. I got stuck on my very first sample code and need some help to get it running. Before I post this question, I did search on stack overflow, found some similar questions but still could not fix it.

Error: Cannot find module 'express'

I am using mac os 10.8.2. I have Node.js installed using nvm.

node.js: 0.8.20 path to node:    /Users/feelexit/nvm/v0.8.20/bin/node
path to express: /Users/feelexit/nvm/node_modules/express

here's my sample code: this file locates at:

/Users/feelexit/WebstormProjects/learnnode/node_modules/index.js

var express = require('express');
var app = express();
app.get('/', function(req, res){
    res.send('welcome to express');
});
app.listen(3000);

when I try to run this command node index.js I get following error message, please help me to fix it.

Thank you.

Error: Cannot find module 'express'
    at Function.Module._resolveFilename (module.js:338:15)
    at Function.Module._load (module.js:280:25)
    at Module.require (module.js:362:17)
    at require (module.js:378:17)
    at Object.<anonymous> (/Users/feelexit/WebstormProjects/learnnode/node_modules/index.js:1:81)
    at Module._compile (module.js:449:26)
    at Object.Module._extensions..js (module.js:467:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Module.runMain (module.js:492:10)
feelexits-Mac:node_modules feelexit$

Update to answer chovy's question:

feelexits-Mac:~ feelexit$ npm install
npm ERR! install Couldn't read dependencies
npm ERR! Error: ENOENT, open '/Users/feelexit/package.json'
npm ERR! If you need help, you may report this log at:
npm ERR!     <http://github.com/isaacs/npm/issues>
npm ERR! or email it to:
npm ERR!     <npm-@googlegroups.com>

npm ERR! System Darwin 12.2.0
npm ERR! command "/Users/feelexit/nvm/v0.8.20/bin/node" "/Users/feelexit/nvm/v0.8.20/bin/npm" "install"
npm ERR! cwd /Users/feelexit
npm ERR! node -v v0.8.20
npm ERR! npm -v 1.2.11
npm ERR! path /Users/feelexit/package.json
npm ERR! code ENOENT
npm ERR! errno 34
npm ERR! 
npm ERR! Additional logging details can be found in:
npm ERR!     /Users/feelexit/npm-debug.log
npm ERR! not ok code 0

May be this will help http://stackoverflow.com/questions/9133784/node-version-manager-nvm-npm-installing-modules-to-common-folder — user568109, Feb 19 '13 at 03:26
Are you certain that the express library is in your "node_modules" folder? You may also want to try moving your _index.js_ file up one directory to "/Users/feelexit/WebstormProjects/learnnode/" and leave the node_modules folder alone. — Default, Feb 19 '13 at 03:53
Please post your `package.json` file. That will help in debugging the problem. — Akhil Raina, Feb 19 '13 at 07:27
@chovy, I use npm install express to install express. what does only "npm install" do ? — qinking126, Feb 19 '13 at 12:12
@Default, yes, it is in the node_modules folder. I moved it one direotry up to "/Users/feelexit/WebstormProjects/learnnode/", still same error. — qinking126, Feb 19 '13 at 12:24
Does your express library have a _package.json_ file in the express/ directory (express/package.json)? Also, I just noticed that you have your express module located in a different directory than your project. That is probably the problem since you are trying to `require()` it locally. Move your express module from _/Users/feelexit/nvm/node_modules/express_ to _/Users/feelexit/WebstormProjects/learnnode/node_modules/express_ and let me know if that solves your problem. [This info](https://npmjs.org/doc/folders.html) can give you more detail about node_module file structures. — Default, Feb 19 '13 at 15:13
possible duplicate of [Node.js Error: Cannot find module express](http://stackoverflow.com/questions/17162308/node-js-error-cannot-find-module-express) — Evan Carroll, Nov 11 '13 at 06:20
Make sure your `package.json` file has all the required libraries before `npm install` I had installed them via the command line previously without the `--save` and they were not in the `package.json` file, so basically my setup was missing dependencies. — , Dec 08 '20 at 19:41

score 218 · Answer 1 · edited Dec 02 '20 at 16:23

218

It says

Cannot find module 'express'

Do you have express installed? If not then run this.

npm install express

and run your program again.

edited Dec 02 '20 at 16:23

Tiago Martins Peres

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answered Jul 18 '13 at 11:03

Saurabh Rana

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2

This does not fix the problem in my case. `npm install express` shows this error `npm ERR! Error: UNKNOWN, symlink '../express/bin/express'`. Seems to be a deeper issue. – Sliq Oct 15 '13 at 00:36
Use sudo if you have not fixed your directory permissions for npm. In any case, "sudo npm install" is a better option. – Gaurav Gupta Dec 10 '14 at 08:04
symlink Errors often occur, if you installed things globally and, yeah, the symlink broke. Try `npm link` to re-create the respective linking... – Frank Nocke May 17 '16 at 11:44
@Sliq I tried with your solution but i can't solve my problem can you help me ? – VjyV Oct 10 '16 at 06:47
Don't overlook "And run your program again." In my case i had to restart the process in my `process manager`. It didn't restart by itself. – Tadej May 08 '17 at 07:40
Prolly too late! But you shall redo npm install, it will fetch all the missing dependency at once. – Saurabh Rana Nov 17 '20 at 03:30
But surely one should be able to run a bundle without dependencies post build, no? – iMe May 29 '22 at 20:03

score 50 · Answer 2 · edited Dec 02 '20 at 16:24

50

After you do express in your terminal, then do

npm install

To install all the dependencies.

Then you can do node app to run the server.

edited Dec 02 '20 at 16:24

Tiago Martins Peres

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answered Nov 01 '13 at 18:03

Bill

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You should point out that this requires a package list file ie .json.. And this is not always the case. – Pogrindis Nov 07 '13 at 11:11
@VjyV in the same directory you have your .js node file. But it should have the package.json file in the directory so that it can install the required dependencies. – Saurabh Rana Dec 20 '16 at 05:41

Reza Ebrahimi · Answer 3 · 2016-06-09T18:53:45.147

39

Check if you have installed express module. If not, use this command:

npm install express

and if your node_modules directory is in another place, set NODE_PATH envirnment variable:

set NODE_PATH=your\directory\to\node_modules;%NODE_PATH%

edited Jun 09 '16 at 18:53

answered Nov 22 '13 at 10:23

Reza Ebrahimi

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**This** is the right answer, to everyone posting these `CTRL+C / CTRL+V` `npm install` answers: do you really think anyone would try to run something without checking if its installed first? Seriously... – Claudio Holanda Jun 14 '14 at 21:45
4

Just adding a minor detail: You need to run the install express command in the directory of your application and **not** in your Node.js installation folder or the npm-folder in AppData. Because that's the mistake I made, because I thought it was some kind of SDK-add-on. – Alex Dec 10 '14 at 12:34

score 36 · Answer 4 · edited Dec 02 '20 at 16:24

36

npm install --save express

This worked for me. Just run express.js installation again.

edited Dec 02 '20 at 16:24

Tiago Martins Peres

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answered May 08 '18 at 14:55

Bonface Ochieng

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score 13 · Answer 5 · answered Nov 30 '13 at 20:19

13

npm install from within your app directory will fix the issue as it will install everything required

answered Nov 30 '13 at 20:19

Eldad

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score 7 · Answer 6 · edited Nov 07 '17 at 22:43

7

Unless you set Node_PATH, the only other option is to install express in the app directory, like npm install express --save. Express may already be installed but node cannot find it for some reason

edited Nov 07 '17 at 22:43

Thomas Fritsch

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answered Nov 07 '17 at 21:56

Shemogumbe

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1

This one worked for me, better execute the install command in same directory as your .js files are. Also you may run command " npm init " to create package.json file to avoid further problems. – emarshah Dec 30 '19 at 23:03

score 5 · Answer 7 · answered Nov 23 '13 at 02:20

5

Digging up an old thread here BUT I had this same error and I resolved by navigating to the directory my NodeApp resides in and running npm install -d

answered Nov 23 '13 at 02:20

Wjdavis5

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Not sure why or how it matters but this installs it in your devdependencies: https://docs.npmjs.com/cli/install – Guy Lowe Dec 01 '15 at 03:36
1

@GuyLowe `-d` is debug for npm, `-D` is dev dependencies. – John Pavek Feb 18 '19 at 22:07

Default · Answer 8 · 2013-02-20T02:58:59.930

3

You have your express module located in a different directory than your project. That is probably the problem since you are trying to require() it locally. Try moving your express module from /Users/feelexit/nvm/node_modules/express to /Users/feelexit/WebstormProjects/learnnode/node_modules/express. This info can give you more detail about node_module file structures.

edited Feb 20 '13 at 02:58

answered Feb 19 '13 at 13:06

Default

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VeXii · Answer 9 · 2013-07-18T11:47:31.447

3

if youre main file is located at /Users/feelexit/WebstormProjects/learnnode/node_modules/index.js then express needs to be located at /Users/feelexit/WebstormProjects/learnnode/node_modules/node_modules as node always looks for modules in ./node_modules (and its internal folder) when the path dont start with ./ or / (more info here)

i think you miss placed youre main file in the module folder

edited Jul 18 '13 at 11:47

answered Jul 18 '13 at 11:13

VeXii

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score 3 · Answer 10 · answered Aug 26 '16 at 00:11

for this scenario run npm install express command using your cmd prompt for the respective folder where you want to run the program. Example I want to run the express module program server.js in F:\nodeSample. So run "npm install express" in that particular folder then run server.js

score 2 · Answer 11 · answered Jan 19 '21 at 21:20

2

Sometimes there are error while installing the node modules Try this:

Delete node_modules
npm install

answered Jan 19 '21 at 21:20

luis fernando yupanqui taco

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score 1 · Answer 12 · answered Aug 22 '16 at 15:48

1

Run npm install express body-parser cookie-parser multer --save command in the same directory with your source code nodejs file to resolve this issue. P/s: check your directory after run command to understand more!

answered Aug 22 '16 at 15:48

Do Tat Hoan

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score 1 · Answer 13 · answered Oct 25 '17 at 14:15

1

In rare cases, npm cache may get corrupt. For me, what worked was:

npm cache clean --force

Generally, the package manager will detect corruption and refetch on its own so this is not usually necessary. However, in my case Windows 10 crashed a few times and I suspect this may have been during a fetch operation. Hope it helps someone!

More information: https://docs.npmjs.com/cli/cache

answered Oct 25 '17 at 14:15

jwerner

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Thanks! In my case node get corrupt after installing BigSur. Cache clean worked! – MoD Feb 28 '21 at 22:08

score 0 · Answer 14 · answered Nov 08 '14 at 11:38

npm ERR! Error: ENOENT, open '/Users/feelexit/package.json'

This happens due to missing permissions or unlinked files while npm was working.

Meaning, that executing npm as this user doesn't have enough rights to read/write from a file, in this case package.json.

try adding sudo before the entire command - it should resolve.

$ sudo npm install -g express
$ Password:*******

Password would be your admin password of your mac.

-g flag will install this module (express) in the global context of node - meaning node will/should recognize express module from within any js file without having to provide a full path to the module in use.

Hope this helps!!

score 0 · Answer 15 · answered Feb 24 '15 at 02:05

0

I had the same problem. My issue was that I have to change to the Node.js project directory on the command line before installing express.

cd /Users/feelexit/WebstormProjects/learnnode/node_modules/

answered Feb 24 '15 at 02:05

user3377708

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score 0 · Answer 16 · answered Jul 25 '16 at 00:26

I'm guessing that this is coursework from Colt Steele's Web Development course... I was looking for the same answer as to why I ended up with that error too.. Colt doesn't say so but you take the node_module folder and move into the new folder you're working in... that's what worked for me.

Sarath Kumar · Answer 17 · 2018-04-17T10:11:35.923

D:\learn\Node.js\node app.js
module.js:549
    throw err;
    ^

Error: Cannot find module 'body-parser'
    at Function.Module._resolveFilename (module.js:547:15)
    at Function.Module._load (module.js:474:25)
    at Module.require (module.js:596:17)
    at require (internal/module.js:11:18)

Sometimes version not match with package.json Fixed the problem by checking the package.json then use the following commands: npm install body-parser@1.13.2 it resolved for me.

score 0 · Answer 18 · answered Apr 17 '18 at 16:24

0

I've came across a similar problem and in the end it was a matter of some old dependencies that were messing up my Heroku server.

While at my project's folder I've run:

npm uninstall
npm install

I hope it helps

answered Apr 17 '18 at 16:24

HClx

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score 0 · Answer 19 · answered May 10 '20 at 17:00

0

Have you tried

npm install

If you're specifically looking for just express

npm install --save express

answered May 10 '20 at 17:00

Akash Yellappa

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score 0 · Answer 20 · answered Oct 31 '21 at 02:43

0

In my case I was trying to run the same as you but using nodemon. The error was the same but the problem was because on my package.json I added app.js instead of just app

"script" : { "dev": "nodemon app" }

answered Oct 31 '21 at 02:43

Yorsh

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node.js, Error: Cannot find module 'express'

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