How do I resolve “Cannot find module” error using

Question

After pulling down a module from GitHub and following the instructions to build it, I try pulling it into an existing project using:

> npm install ../faye

This appears to do the trick:

> npm list
/home/dave/src/server
└─┬ faye@0.7.1
  ├── cookiejar@1.3.0
  ├── hiredis@0.1.13
  └── redis@0.7.1

But Node.js can't find the module:

> node app.js
node.js:201
        throw e; // process.nextTick error, or 'error' event on first tick
              ^
Error: Cannot find module 'faye'
    at Function._resolveFilename (module.js:334:11)
    at Function._load (module.js:279:25)
    at Module.require (module.js:357:17)
    at require (module.js:368:17)
    at Object.<anonymous> (/home/dave/src/server/app.js:2:12)
    at Module._compile (module.js:432:26)
    at Object..js (module.js:450:10)
    at Module.load (module.js:351:31)
    at Function._load (module.js:310:12)
    at Array.0 (module.js:470:10)

I really want to understand what is going on here, but I'm at a bit of a loss as to where to look next. Any suggestions?

Answer 1

Removing node/npm and then re-installing the stable(not the latest) version worked for me.

sudo rm -rf /usr/local/{lib/node{,/.npm,_modules},bin,share/man}/{npm*,node*,man1/node*}

https://nodejs.org/en/download/

Answer 2

This error can be encountered if you are requireing a module that has a missing or incorrect main field in its package.json. Though the module itself is installed, npm/node has to use a single .js file as an entrypoint to your module. If the main field is not there, it defaults to looking for index.js in your module's folder. If your module's main file is not called index.js, it won't be able to require it.

Discovered while turning a browserify-based module into a CommonJS require-able module; browserify didn't care about the missing main field, and so the error had gone unnoticed.

Answer 3

Change the directory and point to your current project folder and then "npm install". .

This will install all dependencies and modules into your project folder.

Answer 4

I faced the same problem when someone else in the team updated package.json in SVN. Merely removing the node_modules directory did not help. How I solved the problem is:

rm -rf node_modules
rm package.json
rm package-lock.json
svn up
npm install
ng build --env=prod

Hope this helps someone!

Answer 5

PRO TIP:

This error happened to me, while fighting fatigue and mild illness, because I typed node blah instead of npm blah.

The error message received wasn't angry enough to alert me to my own folly!

Answer 6

Using npm install installs the module into the current directory only (in a subdirectory called node_modules). Is app.js located under home/dave/src/server/? If not and you want to use the module from any directory, you need to install it globally using npm install -g.

I usually install most packages locally so that they get checked in along with my project code.

Update (8/2019):

Nowadays you can use package-lock.json file, which is automatically generated when npm modifies your node_modules directory. Therefore you can leave out checking in packages, because the package-lock.json tracks the exact versions of your node_modules, you're currently using. To install packages from package-lock.json instead of package.json use the command npm ci.

Update (3/2016):

I've received a lot of flak for my response, specifically that I check in the packages that my code depends on. A few days ago, somebody unpublished all of their packages (https://medium.com/@azerbike/i-ve-just-liberated-my-modules-9045c06be67c#.kq9s64clp) which broke React, Babel, and just about everything else. Hopefully it's clear now that if you have production code, you can't rely on NPM actually maintaining your dependencies for you.