Node.js Error: Cannot find module express

node.js Problem Overview

I wrote my first node.js app, but it can't find express library:

C:\ChatServer\Server>node server.js

module.js:340
    throw err;
          ^
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:364:17)
    at require (module.js:380:17)
    at Object.<anonymous> (C:\ChatServer\Server\server.js:6:9)
    at Object.<anonymous> (C:\ChatServer\Server\server.js:25:4)
    at Module._compile (module.js:456:26)
    at Object.Module._extensions..js (module.js:474:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)

But express is intalled (with -g key):

C:\ChatServer\Server>npm install -g express
npm http GET https://registry.npmjs.org/express
npm http 304 https://registry.npmjs.org/express
npm http GET https://registry.npmjs.org/connect/2.7.11
npm http GET https://registry.npmjs.org/commander/0.6.1
npm http GET https://registry.npmjs.org/range-parser/0.0.4
npm http GET https://registry.npmjs.org/mkdirp/0.3.4
npm http GET https://registry.npmjs.org/cookie/0.1.0
npm http GET https://registry.npmjs.org/buffer-crc32/0.2.1
npm http GET https://registry.npmjs.org/fresh/0.1.0
npm http GET https://registry.npmjs.org/methods/0.0.1
npm http GET https://registry.npmjs.org/send/0.1.0
npm http GET https://registry.npmjs.org/cookie-signature/1.0.1
npm http GET https://registry.npmjs.org/debug
npm http 304 https://registry.npmjs.org/mkdirp/0.3.4
npm http 304 https://registry.npmjs.org/range-parser/0.0.4
npm http 304 https://registry.npmjs.org/cookie/0.1.0
npm http 304 https://registry.npmjs.org/connect/2.7.11
npm http 304 https://registry.npmjs.org/commander/0.6.1
npm WARN package.json [email protected] No repository field.
npm http 304 https://registry.npmjs.org/buffer-crc32/0.2.1
npm http 304 https://registry.npmjs.org/fresh/0.1.0
npm http 304 https://registry.npmjs.org/methods/0.0.1
npm http 304 https://registry.npmjs.org/send/0.1.0
npm http 304 https://registry.npmjs.org/cookie-signature/1.0.1
npm WARN package.json [email protected] No repository field.
npm WARN package.json [email protected] No readme data.
npm WARN package.json [email protected] No repository field.
npm WARN package.json [email protected] No repository field.
npm WARN package.json [email protected] No repository field.
npm http 304 https://registry.npmjs.org/debug
npm http GET https://registry.npmjs.org/mime/1.2.6
npm http GET https://registry.npmjs.org/qs/0.6.5
npm http GET https://registry.npmjs.org/send/0.1.1
npm http GET https://registry.npmjs.org/formidable/1.0.14
npm http GET https://registry.npmjs.org/cookie/0.0.5
npm http GET https://registry.npmjs.org/bytes/0.2.0
npm http GET https://registry.npmjs.org/pause/0.0.1
npm http 304 https://registry.npmjs.org/mime/1.2.6
npm http 304 https://registry.npmjs.org/bytes/0.2.0
npm WARN package.json bytes@0.2.0 No repository field.
npm http 304 https://registry.npmjs.org/pause/0.0.1
npm WARN package.json pause@0.0.1 No repository field.
npm http 304 https://registry.npmjs.org/formidable/1.0.14
npm http 304 https://registry.npmjs.org/qs/0.6.5
npm http 304 https://registry.npmjs.org/send/0.1.1
npm http 304 https://registry.npmjs.org/cookie/0.0.5
npm http GET https://registry.npmjs.org/mime
npm http 304 https://registry.npmjs.org/mime
C:\Users\Dmitry\AppData\Roaming\npm\express -> C:\Users\Dmitry\AppData\Roaming\npm\node_modules\express\bin\express
npm WARN package.json policyfile@0.0.4 'repositories' (plural) Not supported.
npm WARN package.json Please pick one as the 'repository' field
npm WARN package.json assert-plus@0.1.2 No repository field.
npm WARN package.json ctype@0.5.2 No repository field.
express@3.2.6 C:\Users\Dmitry\AppData\Roaming\npm\node_modules\express
├── methods@0.0.1
├── fresh@0.1.0
├── range-parser@0.0.4
├── cookie-signature@1.0.1
├── buffer-crc32@0.2.1
├── cookie@0.1.0
├── debug@0.7.2
├── commander@0.6.1
├── mkdirp@0.3.4
├── send@0.1.0 (mime@1.2.6)
└── connect@2.7.11 (pause@0.0.1, qs@0.6.5, bytes@0.2.0, cookie@0.0.5, formidable@1.0.14, send@0.1.1)

Some information:

C:\ChatServer\Server>npm --version
1.2.24

C:\ChatServer\Server>node --version
v0.10.9

C:\ChatServer\Server>npm --version
1.2.24

C:\ChatServer\Server>npm ls -g installed express
npm WARN package.json cookie-signature@1.0.1 No repository field.
npm WARN package.json fresh@0.1.0 No repository field.
npm WARN package.json methods@0.0.1 No repository field.
npm WARN package.json range-parser@0.0.4 No repository field.
npm WARN package.json send@0.1.0 No repository field.
npm WARN package.json policyfile@0.0.4 'repositories' (plural) Not supported.
npm WARN package.json Please pick one as the 'repository' field
npm WARN package.json bytes@0.2.0 No repository field.
npm WARN package.json pause@0.0.1 No repository field.
npm WARN package.json assert-plus@0.1.2 No repository field.
npm WARN package.json ctype@0.5.2 No repository field.
C:\Users\Dmitry\AppData\Roaming\npm
└── express@3.2.6


C:\ChatServer\Server>npm ls installed express
C:\ChatServer\Server
└── (empty)

How can I solve this problem? (MUST I install it without -g?)

node.js Solutions

Solution 1 - node.js

You need to install Express locally into the context of your application (node_modules folder):

$ npm install express

The reason for this is that applications always look in their local context for any dependencies. The global installation is only for setting up system-wide available binaries, such as unit test runners or bootstrappers or things like that.

With Express, when you install it globally, you get an express binary that can bootstrap an application for you. For more information, type

$ express --help

So, to answer your final question: YES, you need to install it without -g.

Solution 2 - node.js

For me it worked when installed express locally with --save option as follow:

$ npm install express --save

Solution 3 - node.js

Check if you are not install express module, 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%

Solution 4 - node.js

Golo have explain well the solution, but I might add a clarification:
sometimes node modules are installed in

/usr/local/lib/node_modules

and when you launch node blabla.js modules are searched in

/lib

So a solution is to create a symbolic link:

sudo ln -s /usr/local/lib/node_modules/ /lib/node_modules

Solution 5 - node.js

In your case your express module is installed at C:\Users\Dmitry\AppData\Roaming\npm\node_modules\express, but you need to get this module in to your project directory. So you should copy the file the express module folders from C:\Users\Dmitry\AppData\Roaming\npm\node_modules\ to your project directory as : C:\ChatServer\Server\node_modules. If you do not have a folder named 'node_modules' in your project folder, then create it first and paste those files into this folder. This method worked for me on my windows pc. Restart your node server and once again run the command node C:\ChatServer\Server>node server.js. It should work now !!!!

Solution 6 - node.js

Given you have installed node on your system, install Express locally for your project using the following for Windows:

npm install express

npm install express --save

You might give it global access by using:

npm install -g express --save

Solution 7 - node.js

On Ubuntu-based OS you can try

sudo apt-get install node-express

its working for me on Mint

Solution 8 - node.js

installing express globally will not work on your local project so you need to install it locally for use .

npm install express

Hope this will work

Thank you

Solution 9 - node.js

I had this error in vscode, although the modules where installed. I am using typescript and express. In the server.ts files all the imports had red squiggly underlines. It turns out I had a faulty tsconfig.json file.

{
    "compileOnSave": false,
    "compilerOptions": {
        "module": "commonjs", // Previously this value was `es6`
        "target": "es6",
        "allowSyntheticDefaultImports": true,
        "baseUrl": "public",
        "sourceMap": true,
        "outDir": "dist",
        "jsx": "react",
        "strict": true,
        "preserveConstEnums": true,
        "removeComments": true,
        "noImplicitAny": true,
        "allowJs": true
    },
    "exclude": [
        "node_modules",
        "build"
    ]
}

Solution 10 - node.js

create one folder in your harddisk e.g sample1 and go to command prompt type :cd and gives the path of sample1 folder and then install all modules... > npm install express > >npm install jade > >npm install socket.io

and then whatever you are creating application save in sample1 folder

try it...

Solution 11 - node.js

go to your application directory and install the express module using the below command npm install express --save then list the all install module using the below command npm ls you will see all the locally install modules.

Solution 12 - node.js

I had the same error following the example on this book: "Kubernetes Up & Running".
I see many answers suggesting to install express "by hand" but I'm not convinced is the best solution.
Because we are using package.json (I can see it in the logs) and the right way to build the app is running npm install, I added the express dependency in the package.json file.

 "dependencies": {
    "express": "^4.17.1"
}

I get the current version with npm search express.

Solution 13 - node.js

I hit the same problem. I had express installed globally at /usr/local/bin/. When I do 'npm install', express was not created in node_modules of local directory.

Check if you have file name .npmrc in your $HOME
If it has 'global = true', change to 'global = false'
Now do 'npm install' in application directory. More likely, you should get all package dependent modules installed in node_modules (local) within application directory.

Solution 14 - node.js

sudo brew uninstall node
brew update
brew upgrade
brew cleanup
brew install node
sudo chown -R $(whoami) /usr/local
brew link --overwrite node
sudo brew postinstall node

This worked for me on MacOS X Sierra

Solution 15 - node.js

I'm not proud sharing this, but in my case I had:

 require('express.handlebars')

 //and the correct form is:
 require('express-handlebars'); //Use dash instead.

Solution 16 - node.js

1.first check if express is install at correct location. 2. npm install express (run this command).

express will save under your "node_modules" folder

Content Type	Original Author	Original Content on Stackoverflow
Question	Dmitry	View Question on Stackoverflow
Solution 1 - node.js	Golo Roden	View Answer on Stackoverflow
Solution 2 - node.js	Mustafamg	View Answer on Stackoverflow
Solution 3 - node.js	Reza Ebrahimi	View Answer on Stackoverflow
Solution 4 - node.js	Luca Davanzo	View Answer on Stackoverflow
Solution 5 - node.js	Rahul Gupta	View Answer on Stackoverflow
Solution 6 - node.js	Krishna Ganeriwal	View Answer on Stackoverflow
Solution 7 - node.js	Nickolay Savchenko	View Answer on Stackoverflow
Solution 8 - node.js	MD SHAYON	View Answer on Stackoverflow
Solution 9 - node.js	Adrian Moisa	View Answer on Stackoverflow
Solution 10 - node.js	Dev	View Answer on Stackoverflow
Solution 11 - node.js	Anayatullah Khan	View Answer on Stackoverflow
Solution 12 - node.js	Alex 75	View Answer on Stackoverflow
Solution 13 - node.js	user2512153	View Answer on Stackoverflow
Solution 14 - node.js	Durul Dalkanat	View Answer on Stackoverflow
Solution 15 - node.js	David Castro	View Answer on Stackoverflow
Solution 16 - node.js	Divesh singh	View Answer on Stackoverflow