local package npm error - node.js

Question

I added this dependency to my package.json :
"user": "file:./server/models/user"
Inside my user file I've got module.exports = function() {...}
npm ERR! addLocal Could not install /home/WebstormProjects/project/server/models/user
npm ERR! Linux 3.19.0-30-generic
npm ERR! argv "/usr/bin/nodejs" "/usr/bin/npm" "install"
npm ERR! node v4.1.1
npm ERR! npm v2.14.4
npm ERR! path /home/WebstormProjects/project/server/models/user
npm ERR! code ENOENT
npm ERR! errno -2
npm ERR! syscall open
npm ERR! enoent ENOENT: no such file or directory, open '/home/WebstormProjects/project/server/models/user'
npm ERR! enoent This is most likely not a problem with npm itself
npm ERR! enoent and is related to npm not being able to find a file.
npm ERR! enoent
npm ERR! Please include the following file with any support request:
npm ERR! /home/WebstormProjects/project/npm-debug.log
I did follow the doc : https://docs.npmjs.com/files/package.json#local-paths

Answer 1

The error messages aren't very helpful, but it has to be (emphasis mine):
a path to a local directory that contains a package
https://docs.npmjs.com/files/package.json#local-paths
You appear to be pointing it to a file. You probably need something like:
"user": "file:./server/models"
A package also requires a package.json, so in that case you'd need to have server/models/package.json.