How to Install npm, Master npm Commands & Use Packages

This comprehensive guide walks you through installing npm and mastering its command-line interface. We'll cover installing packages locally and globally, managing dependencies, and ensuring your project's security.

Node.js empowers server-side JavaScript development, built on the V8 JavaScript engine and written in C for speed. Initially designed for server applications, its use expanded to local task automation, spawning a rich ecosystem of tools (Grunt, Gulp, webpack) that revolutionized front-end development. npm is the key to managing these tools (or packages) within Node.js, simplifying installation and management.

This tutorial covers fundamental npm operations: local and global package installation, deletion, updating, version-specific installation, and dependency management using package.json. For a visual learning experience, consider SitePoint Premium's free screencast: "What is npm and How Can I Use It?"

Before using npm, you must install Node.js.

Key Concepts:

• Installation: npm is bundled with Node.js; download from the official site, verify installation using npm --version.
• Global vs. Local: Install packages globally (system-wide) or locally (per project), typically managed via package.json.
• Updating npm: Regularly update npm for new features and improvements; OS-specific update commands apply.
• Dependency Management: package.json efficiently handles project dependencies, ensuring consistent setups across environments using package-lock.json.
• Security: Use npm audit to detect vulnerabilities in project dependencies and apply recommended fixes.
• npx: Execute npm packages without global installation, simplifying testing of new tools.

Installing npm with Node.js:

Download Node.js from the official Node.js download page. Installers are available for Windows and macOS, along with pre-compiled Linux binaries and source code. Linux users can also install via their package manager.

This tutorial uses a recent Long Term Support (LTS) version of Node.js. Consider using a Node version manager for easier version control.

Verify the installation:

which node
node --version
node  //enter Node's REPL

Confirm npm installation:

which npm
npm --version

Updating npm:

Update npm to the latest version (commands may vary slightly by OS):

Linux/macOS:

npm install -g npm@latest

Windows: Use the npm-windows-upgrade tool (requires elevated PowerShell):

which node
node --version
node  //enter Node's REPL

Node Packaged Modules (Local vs. Global):

npm installs packages locally (in node_modules within your project) or globally (system-wide). Avoid global installations in system directories due to potential permission issues; instead, configure a user-specific global location.

Changing the Global npm Package Location:

1. Create a directory: mkdir ~/.node_modules_global
2. Configure npm: npm config set prefix=$HOME/.node_modules_global
3. Reinstall npm: npm install npm@latest -g
4. Update PATH: Add export PATH="$HOME/.node_modules_global/bin:$PATH" to your shell's configuration file (.bashrc, .zshrc, etc.) and restart your terminal.

Installing Packages (Global Mode):

Install a package globally (e.g., UglifyJS):

which npm
npm --version

List globally installed packages:

npm install -g npm@latest

Installing Packages (Local Mode):

1. Create a project directory and initialize package.json: npm init -y
2. Install a local package (e.g., Underscore): npm install underscore

This adds the package to package.json's dependencies section and creates a package-lock.json file.

Managing Dependencies with package.json:

package.json lists project dependencies, ensuring consistent setups across environments. The package-lock.json file guarantees exact dependency versions.

Uninstalling Local Packages:

Uninstall a package: npm uninstall underscore

Installing Specific Package Versions:

Install a specific version: npm install underscore@1.9.1

Updating Packages:

Check for updates: npm outdated

Update a package: npm update underscore (or npm update for all outdated packages)

Searching for Packages:

Search for packages: npm search mkdir

Re-installing Project Dependencies:

Remove node_modules and reinstall: rm -rf node_modules && npm install

Managing npm's Cache:

Clear the cache: npm cache clean --force

Using npm audit for Security:

Scan for vulnerabilities: npm audit

Fix vulnerabilities: npm audit fix (or npm audit fix --force to allow breaking changes)

npm Aliases:

• npm i: npm install
• npm un: npm uninstall
• npm up: npm update
• npm ls: npm list

Executing Packages with npx:

Execute packages without global installation: npx http-server

Conclusion:

This guide provides a solid foundation for using npm. Explore further by comparing npm and Yarn, using Node Version Manager (nvm), hosting private npm packages, or learning about Deno's package management. npm's expanding role in front-end development makes it an essential tool for modern JavaScript developers.

FAQs (Included in original text): The FAQs section from the original text is already comprehensive and well-written; no changes are needed.

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