Install dependencies globally and locally using package.json


Question

Using npm we can install the modules globally using -g option. How can we do this in the package.json file?

Suppose, these are my dependencies in package.json file

"dependencies": {
    "mongoose": "1.4.0",
    "node.io" : "0.3.3",
    "jquery"  : "1.5.1",
    "jsdom"   : "0.2.0",
    "cron"    : "0.1.2"
  }

When i run npm install, I want only node.io to be installed globally, the rest others should be installed locally. Is there an option for this?

1
178
2/1/2013 3:23:10 PM

Accepted Answer

New Note: You probably don't want or need to do this. What you probably want to do is just put those types of command dependencies for build/test etc. in the devDependencies section of your package.json. Anytime you use something from scripts in package.json your devDependencies commands (in node_modules/.bin) act as if they are in your path.

For example:

npm i --save-dev mocha # Install test runner locally
npm i --save-dev babel # Install current babel locally

Then in package.json:

// devDependencies has mocha and babel now

"scripts": {
  "test": "mocha",
  "build": "babel -d lib src",
  "prepublish": "babel -d lib src"
}

Then at your command prompt you can run:

npm run build # finds babel
npm test # finds mocha

npm publish # will run babel first

But if you really want to install globally, you can add a preinstall in the scripts section of the package.json:

"scripts": {
  "preinstall": "npm i -g themodule"
}

So actually my npm install executes npm install again .. which is weird but seems to work.

Note: you might have issues if you are using the most common setup for npm where global Node package installs required sudo. One option is to change your npm configuration so this isn't necessary:

npm config set prefix ~/npm, add $HOME/npm/bin to $PATH by appending export PATH=$HOME/npm/bin:$PATH to your ~/.bashrc.

206
11/8/2015 9:57:41 AM

Due to the disadvantages described below, I would recommend following the accepted answer:

Use npm install --save-dev [package_name] then execute scripts with:

$ npm run lint
$ npm run build
$ npm test

My original but not recommended answer follows.


Instead of using a global install, you could add the package to your devDependencies (--save-dev) and then run the binary from anywhere inside your project:

"$(npm bin)/<executable_name>" <arguments>...

In your case:

"$(npm bin)"/node.io --help

This engineer provided an npm-exec alias as a shortcut. This engineer uses a shellscript called env.sh. But I prefer to use $(npm bin) directly, to avoid any extra file or setup.

Although it makes each call a little larger, it should just work, preventing:

  • potential dependency conflicts with global packages (@nalply)
  • the need for sudo
  • the need to set up an npm prefix (although I recommend using one anyway)

Disadvantages:

  • $(npm bin) won't work on Windows.
  • Tools deeper in your dev tree will not appear in the npm bin folder. (Install npm-run or npm-which to find them.)

It seems a better solution is to place common tasks (such as building and minifying) in the "scripts" section of your package.json, as Jason demonstrates above.


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