Basics of package management with npm

Things I want to do

This is a brief explanation of npm, which often comes up when researching Node.js or JavaScript/TypeScript.

This section summarizes the basics of package management.

What is NPM?

NPM is a package management system used with Node.js.

(In reality, it has various functions in addition to package management, such as package execution.)

Official page

npm | Home

www.npmjs.com

install

Package installation using NPM is performed using the following command.

npm install packageName

The command `install` can also be replaced with any of the following: `add`, `i`, `in`, `ins`, `inst`, `insta`, `instal`, `isnt`, `isnta`, `isntal`, or `isntall`.

I think the actual commands you’ll see are ‘install’ or ‘i’.

Options regarding the installation location

Local installation

If you don’t specify an installation location, or if you set –save-prod and -P, it will be installed in the node_modules folder within the project.

Installation information is stored in the ‘dependencies’ section of package.json.　

example:

npm install app

Local installation (dev)

Setting –save-dev and -D will install it into the node_modules folder within your project.

Installation information is stored in ‘devDependencies’ within package.json.　

example:

npm install app -D

Global installation

 Setting –global and -G will install the software outside of the project.

The path is automatically configured, allowing you to run installed packages from anywhere.

example:

npm install app -G

The difference between –save-prod (no options) and –save-dev

If you install using –save-prod (without any options), the installed packages will be included in the final output, but if you install using –save-dev, they will not be included.

In short, libraries referenced from HTML and JS (such as jQuery and threejs) should be installed with –save-prod (no options), while packages for the environment and build process (such as Electron and TypeScript) should be installed with –save-dev.

install without arguments

When you run `install` without any arguments, as shown below, it will automatically read the necessary packages from `Package.json`, etc. This is useful when you’ve cloned a template from Git, etc., and need to retrieve the necessary packages.

npm install

List of installed packages

The following command can be used to list packages using NPM.

npm ls

`install` can be replaced with any of the `list` commands.

Options regarding the installation location

Similar to installation, if no arguments are specified, a list of locally installed packages will be displayed. (However, there is no distinction between Dependencies and devDependencies.)

example:

npm ls

Use the -g option to list globally installed packages.

example:

npm ls -g

Uninstall

Package installation using NPM is performed using the following command.

npm uninstall packageName

Uninstall can be replaced with any of the following: unlink, remove, rm, r, or un.

You can check the installed packages using `npm ls`, as explained in ‘List of installed packages’. (The version name will also be displayed, but you don’t need the version name.)

Packages installed with –save-dev (-D) or –global (-G) must also be uninstalled using –save-dev (-D) or –global (-G).