There are two ways to install npm packages: locally or globally. You choose which kind of installation to use based on how you want to use the package.
If you want to depend on the package from your own module using something like Node.js'
require, then you want to install locally, which is
npm install's default behavior.
On the other hand, if you want to use it as a command line tool, something like the grunt CLI,
then you want to install it globally.
To learn more about the
install command's behavior, check out the CLI doc page.
A package can be downloaded with the command:
> npm install <package_name>
This will create the
node_modules directory in your current directory (if one doesn't exist yet)
and will download the package to that directory.
To confirm that
npm install worked correctly, check to see that a
directory exists and that it contains a directory for the package(s) you installed.
You can do this by running
ls node_modules on Unix systems, e.g. "OSX", "Debian", or
Install a package called
lodash. Confirm that it ran successfully by listing the
contents of the
node_modules directory and seeing a directory called
> npm install lodash > ls node_modules # use `dir` for Windows #=> lodash
If there is no
package.json file in the local directory, the latest version of the
package is installed.
If there is
package.json file, the latest version satisfying the semver rule
package.json for that package (if there is any) is installed.
Once the package is in
node_modules, you can use it in your code. For example, if you
are creating a Node.js module, you can
Create a file named
index.js, with the following code:
// index.jsvar lodash = ;var output = lodash;console;
Run the code using
node index.js. It should output
If you had not properly installed
lodash, you would receive this error:
module.js:340 throw err; ^ Error: Cannot find module 'lodash'
To fix this, run
npm install lodash in the same directory as your
Last modified September 19, 2017 Found a typo? Send a pull request!