How to use package installed locally in node_modules?
Question
How do I use a local version of a module in node.js. For example, in my app, I installed coffee-script:
npm install coffee-script
This installs it in ./node_modules and the coffee command is in ./node_modules/.bin/coffee. Is there a way to run this command when I'm in my project's main folder? I guess I'm looking for something similar to bundle exec in bundler. Basically, I'd like to specify a version of coffee-script that everyone involved with the project should use.
I know I can add the -g flag to install it globally so coffee works fine anywhere, but what if I wanted to have different versions of coffee per project?
Accepted Answer
UPDATE: As Seyeong Jeong points out in their answer below, since npm 5.2.0 you can use npx [command], which is more convenient.
OLD ANSWER for versions before 5.2.0:
The problem with putting
./node_modules/.bin
into your PATH is that it only works when your current working directory is the root of your project directory structure (i.e. the location of node_modules)
Independent of what your working directory is, you can get the path of locally installed binaries with
npm bin
To execute a locally installed coffee binary independent of where you are in the project directory hierarchy you can use this bash construct
PATH=$(npm bin):$PATH coffee
I aliased this to npm-exec
alias npm-exec='PATH=$(npm bin):$PATH'
So, now I can
npm-exec coffee
to run the correct copy of coffee no matter of where I am
$ pwd
/Users/regular/project1
$ npm-exec which coffee
/Users/regular/project1/node_modules/.bin/coffee
$ cd lib/
$ npm-exec which coffee
/Users/regular/project1/node_modules/.bin/coffee
$ cd ~/project2
$ npm-exec which coffee
/Users/regular/project2/node_modules/.bin/coffee
Popular Answer
You don't have to manipulate $PATH anymore!
From npm@5.2.0, npm ships with npx package which lets you run commands from a local node_modules/.bin or from a central cache.
Simply run:
$ npx [options] <command>[@version] [command-arg]...
By default, npx will check whether <command> exists in $PATH, or in the local project binaries, and execute that.
Calling npx <command> when <command> isn't already in your $PATH will automatically install a package with that name from the NPM registry for you, and invoke it. When it's done, the installed package won’t be anywhere in your globals, so you won’t have to worry about pollution in the long-term. You can prevent this behaviour by providing --no-install option.
For npm < 5.2.0, you can install npx package manually by running the following command:
$ npm install -g npx