Dave Causey Dave Causey - 6 months ago 32
Node.js Question

NodeJS - How to resolve "Cannot find module" error

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 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

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 (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 A few days ago, somebody unpublished all of their packages (https://medium.com/@azerbike/i-ve-just-liberated-my-modules-9045c06be67c#.kq9s64clp) which broke React, Babel, and just about everything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.

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