How to use or execute a package installed using npm
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How to include and use in your code a package installed in your node_modules folder
When you install using npm
a package into your node_modules
folder, or also globally, how do you use it in your Node code?
Say you install lodash
, the popular JavaScript utility library, using
npm install lodash
This is going to install the package in the local node_modules
folder.
To use it in your code, you just need to import it into your program using require
:
const _ = require('lodash')
What if your package is an executable?
In this case, it will put the executable file under the node_modules/.bin/
folder.
One easy way to demonstrate this is cowsay.
The cowsay package provides a command line program that can be executed to make a cow say something (and other animals as well 🦊).
When you install the package using npm install cowsay
, it will install itself and a few dependencies in the node_modules folder:
There is a hidden .bin folder, which contains symbolic links to the cowsay binaries:
How do you execute those?
You can of course type ./node_modules/.bin/cowsay
to run it, and it works, but npx, included in the recent versions of npm (since 5.2), is a much better option. You just run:
npx cowsay
and npx will find the package location.
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