node.js - How to use executables from a 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?

Answer 1

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