how to specify local modules as npm package depend

Question

I have an application which has the usual set of dependencies on third party modules (e.g. 'express') specified in the package.json file under dependencies. E.g.

"express"     : "3.1.1"

I would like to structure my own code modularly and have a set of local (meaning on the file system i am currently in) modules be installed by the package.json. I know that i can install a local module by running:

npm install path/to/mymodule

However, I don't know how to make this happen via the package.json dependencies structure. Using the --save option in this command is simply putting "mymodule": "0.0.0" into my package.json (doesn't reference the filepath location). If i then remove the installed version from node_modules, and try to re-install from the package.json, it fails (because it looks for "mymodule" in the central registry, and doesn't look locally).

I'm sure the is a way of telling the "dependencies": {} structure that I want it to be installed from a file system path, but don't know how.

Anyone else had this problem? Thanks.

Answer 1

If it's acceptible to simply publish your modules preinstalled in node_modules alongside your other files, you can do it like this:

// ./node_modules/foo/package.json
{ 
  "name":"foo",
  "version":"0.0.1",
  "main":"index.js"
}

// ./package.json
...
"dependencies": {
  "foo":"0.0.1",
  "bar":"*"
}

// ./app.js
var foo = require('foo');

You may also want to store your module on git and tell your parent package.json to install the dependency from git: https://npmjs.org/doc/json.html#Git-URLs-as-Dependencies

Answer 2

As of NPM 2.0.0, importing local dependencies is supported natively. This was documented by danilopopeye in response to a similar question. I've copied his response here to help anyone needing to find the correct answer, as this question ranks very highly in Google's search results.

This feature was implemented in the version 2.0.0 of npm. For example:

{
  "name": "baz",
  "dependencies": {
    "bar": "file:../foo/bar"
  }
}

Any of the following paths are also valid:

../foo/bar
~/foo/bar
./foo/bar
/foo/bar

Answer 3

See: Local dependency in package.json

It looks like the answer is npm link: https://docs.npmjs.com/cli/link

Answer 4

I couldn't find a neat way in the end so I went for create a directory called local_modules and then added this bashscript to the package.json in scripts->preinstall

#!/bin/sh
for i in $(find ./local_modules -type d -maxdepth 1) ; do
    packageJson="${i}/package.json"
    if [ -f "${packageJson}" ]; then
        echo "installing ${i}..."
        npm install "${i}"
    fi
done

Answer 5

After struggling much with the npm link command (suggested solution for developing local modules without publishing them to a registry or maintaining a separate copy in the node_modules folder), I built a small npm module to help with this issue.

The fix requires two easy steps.

First:

npm install lib-manager --save-dev

Second, add this to your package.json:

{  
  "name": "yourModuleName",  
  // ...
  "scripts": {
    "postinstall": "./node_modules/.bin/local-link"
  }
}

More details at https://www.npmjs.com/package/lib-manager. Hope it helps someone.