There are two ways to install npm packages: locally or globally. Choose which kind of installation to use based on how you want to use the package.
require, then you want to install locally. This is npm install's default behavior.To learn more about the install command, 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 node_modules directory exists and that it contains a directory for the package(s) you installed.
Install a package called lodash. Confirm that it ran successfully by listing the contents of the node_modules directory, where you should see a directory called lodash.
C:\ npm install lodash
C:\ dir node_modules
#=> lodash
> npm install lodash
> ls node_modules
#=> lodash
If there is no package.json file in the local directory, the latest version of the package is installed.
If there is a package.json file, npm installs the latest version that satisfies the semver rule declared in package.json.
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 require it.
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 [2, 3].
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 index.js.
Last modified December 22, 2017 Found a typo? Send a pull request!