how to specify local modules as npm package dependencies

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

npm install now supports this

npm install --save ../path/to/mymodule

For this to work mymodule must be configured as a module with its own package.json. See Creating NodeJS modules.

As of npm 2.0, local dependencies are supported natively. See danilopopeye's answer to a similar question. I've copied his response here as this question ranks very high in web 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

syncing updates

Since npm install copies mymodule into node_modules, changes in mymodule's source will not automatically be seen by the dependent project.

There are two ways to update the dependent project with

• Update the version of mymodule and then use npm update: As you can see above, the package.json "dependencies" entry does not include a version specifier as you would see for normal dependencies. Instead, for local dependencies, npm update just tries to make sure the latest version is installed, as determined by mymodule's package.json. See chriskelly's answer to this specific problem.

• Reinstall using npm install. This will install whatever is at mymodule's source path, even if it is older, or has an alternate branch checked out, whatever.